Photoactive materials

ABSTRACT

Photoreactive dendrimers comprising a core portion, branching units and terminal groups, wherein at least one terminal group and/or branching unit is a photoreactive group and wherein the photo reactive groups include preferably cinnamates, coumarins, benzylidenephthalimidines, benzylideneacetophenones, diphenylacetylenes stilbazoles, uracyl, quinolinone, maleinimides, or cinnamylidene acetic acid derivatives and are able to undergo photocyclization, in particular [2+2]-photocyclization.

[0001] The present invention relates to the use of photoreactivedendrimers as orientation layers for liquid crystals and in theconstruction of unstructured and structured optical elements andmulti-layer systems. Further, the present invention also relates to newphotoreactive dendrimers.

[0002] The successful functioning of a liquid crystal device depends onthe ability of the liquid crystal molecules within that device to adoptand maintain an imposed alignment. Alignment of the liquid crystalmolecules is achieved by use of an orientation layer which defines adirection of orientation for the liquid crystal molecules of the devicewith the result that the longitudinal axes of the molecules becomealigned with the direction of orientation defined by the orientationlayer. In addition to this directional alignment, the orientation layeris also able to impart to the liquid crystal molecules an angle of tiltso that the molecules align themselves at an angle to the surface of theorientation layer rather than lying parallel hereto.

[0003] Tilt angles from 1° to 15° are usual for nematic liquid crystaldisplays (LCDs). Some electro-optical effects used for LCDs howeverrequire alignment layers with very high pretilt angles. Verticallyaligned nematic (VAN) LCDs for instance require pretilt angles between85° and 90°, measured from the surface plane. In the case of hybridaligned nematic (HAN) LCDs, the pretilt angle at one of the substrateshas to be in the above range, whereas the tilt angle at the othersubstrate is low (typically 0° to 10°).

[0004] Methods of preparing orientation layers for liquid crystalmaterials are well known to a skilled person. Customarily useduniaxially rubbed polymer orientation layers such as, for example,polyimides however impact a series of disadvantages like dust generationduring the rubbing process and destruction of thin film transistors.Furthermore, the rubbing process does not allow the production ofstructured layers.

[0005] Orientation layers in which the direction of orientation can bepredetermined by irradiation with polarized light have been known forsome time. It is by that means possible to avoid the problems inherentto the rubbing process. In addition, it is possible to provide areashaving different orientation and thus to structure the orientation layeras described for example in Jpn. J. Appl. Phys., 31 (1992), 2155-2164(Schadt et al.). In that process the dimerisation of polymer-bondedphotoactive cinnamic acid groups induced by irradiation with linearlypolarized light is employed leading to an anisotropic polymer network.Those photo-oriented polymer networks can be used wherever structured orunstructured liquid crystal orientation layers are required.

[0006] In addition to their use in LCDs, such orientation layers canalso be used, for example, in the production of so-called hybrid layers,as exemplified for instance in U.S. Pat. No. 5,602,661, European patentapplication EP-A-0689084 (both F. Hoffmann-La Roche AG) andWO-A-98/52077 (Rolic AG). Using those hybrid layers of photostructurableorientation polymers and crosslinkable low molecular weight liquidcrystals, it is possible to realize optical elements such as, forexample, non-absorptive color filters, linear and circular polarizers,optical delay layers and so on.

[0007] For instance EP-A-0611786 and WO-A-96/10049 (both F. Hoffmann-LaRoche AG), as well as EP-A-0763552 (Rolic AG), describe cinnamic acidpolymers that are suitable in principle for the synthesis of suchanisotropically crosslinked, photostructured orientation layers forliquid crystals. In the case of the compounds described in EP-A-0763552and WO-A-96/10049, on irradiation with linearly polarized light it ispossible to induce, in addition to the desired orientation,simultaneously an angle of tilt. This allows the production of layershaving structuring in respect of surface orientation and angle of tilt.

[0008] Photoactive materials for orientation layers were also describedin WO-A-99/49360 (Rolic AG), JP-A-10-195296, JP-A-10-232400 (bothSarnsung Electron Devices Co., Ltd.), WO-A-99/15576 (Rolic AG) andWO-A-99/51662 (Kanegafuchi Kagaku Kogyo KK). In WO-A-99/15576 andWO-A-99/51662 polyimides incorporating photoactive cinnamate groups intheir side chains are described. In WO-A-99/49360, JP-A-10-195296 andJP-A-10-232400 blends of polymeric compounds containing photoactivepolymers on the one hand, and polyimides on the other hand are proposed.A disadvantage of such blends is their limited miscibility. Low contentsof photoactive polymers however lead to a loss of orienting propertiesand consequently to a reduced contrast ratio of liquid crystal layers tobe oriented whereas a reduced polyimide content results in insufficientholding ratios.

[0009] Recently, mixtures of liquid crystal monomers havingcross-linkable groups and photo-orientable monomeric, oligomeric orpolymeric compounds were described in WO-99/64924. Layers of suchmixtures can be photoaligned by linearly polarized light andsubsequently, or simultaneously, cross-linked. As a consequence, only asingle layer is necessary to prepare a variety of coatings such asoptical retarders, polarizing interference filters, structuredpolarizers as well as aligning layers for liquid crystals.

[0010] The use of photo-orientable polymeric compounds in such mixturesleads to a good alignment. A disadvantage of such mixtures is the oftenlimited miscibility between the polymers and liquid crystal monomers,which bears the risk of a limited thermal stability, mainly due to aphase separation upon annealing at high temperatures. On the other hand,known photo-orientable materials of low molecular weight usually havinggood miscibility show poor alignment.

[0011] Generally, the ability of the resulting orientation layers toperform their function depends, in part, on the number of molecules inthe layer that have been isomerised and/or dimerised as a result ofirradiation with linearly polarized light. The extent to which themolecules are isomerised and/or dimerised depends in turn on theirradiation time, the irradiation energy and the structure of themolecules being irradiated.

[0012] However, a problem with low molecular weight materials used inthe preparation of photo-oriented orientation layers is that either acrosslinking prior to irradiation and/or relatively long irradiationtimes are required to make efficient isomerisation and/or dimerisationof the component molecules. In general, when photo-orientable lowmolecular weight materials are mixed with liquid crystalline monomers,the possibility to find photo-active groups in register that can beisomerised and/or dimerised decreases. Consequently, there is a need forstable photoalignable materials with short irradiation time, goodmiscibility and good processability.

[0013] The inventors have now found that photoreactive dendrimersaddress that need. Photoreactive dendrimers can be used to produceorientation layers for liquid crystals and in the construction ofunstructured and structured optical elements and multi-layer systems. Ina second aspect, the invention provides new photoreactive dendrimers ofgood processability that, when irradiated over a relatively short timewith polarized light, result in stable, high-resolution patternableorientation layers which also may induce an angle of tilt.

[0014] These molecules have better miscibility with low molecular weightmaterials such as liquid crystalline monomers (LCPs), as well as withpolymers. Furthermore, cross-linkable or non cross-linkable lowmolecular weight molecules with specific functional groups, such asacrylates, silanes, etc., can be easily incorporated into the mixtures,or chemically linked to the dendrimers, in order to control physicalproperties such as pretilt, and to enhance the adhesion and wetting aswell as long term mechanical, thermal and light stability.

[0015] The architecture of dendrimers is for instance described inAdvances in polymer science, Vol. 142 (1999). Examples are shown in FIG.1.

[0016] Dendrimers as used in the present invention have a core portion,branches and terminal portions. The first branching unit linked to thecore portion is called the first generation of the dendrimer. The nextbranching unit linked to first generation, is called the secondgeneration, etc. The last generation to which the terminal groups arelinked is called the outermost generation of the dendrimer.

[0017] Preferably, at least one terminal group and/or branching unit isa photoreactive group.

[0018] Preferably, the photoreactive groups are able to undergophotocyclization, in particular [2+2]-photocyclization.

[0019] Preferably, the photoreactive groups are sensitive to UV or laserlight, in particular linearly polarized UV light.

[0020] Preferred photoreactive groups are cinnamates, coumarins,benzylidenephthalimidines, benzylideneacetophenones, diphenylacetylenesstilbazoles, uracyl, quinolinone, maleinimides, or cinnamylidene aceticacid derivatives, particularly preferred groups are cinnamates,coumarins, benzylideneacetophenones, or maleimides.

[0021] Most preferred photoreactive groups are cinnamates or coumarins,in particular photoreactive groups represented by the general formulaeIa and Ib:

[0022] wherein the broken line indicates the point of linkage to theoutermost generation of the dendrimer and

[0023] A represents pyrimidine-2,5-diyl, pyridine-2,5-diyl,2,5-thiophenylene, 2,5-furanylene, 1,4- or 2,6-naphthylene; orphenylene, which is unsubstituted or mono- or poly-substituted byfluorine, chlorine or by a cyclic, straight-chain or branched alkylresidue which is unsubstituted mono- or poly-substituted by fluorine,chlorine, having 1 to 18 carbon atoms, wherein one or more non-adjacent—CH₂— groups may independently be replaced by a group C; wherein

[0024] C represents a group selected from —O—, —CO—, —CO—O—, —O—CO—,—NR¹—, —NR¹—CO—, —CO—NR¹—, —NR¹—CO—O—, —O—CO—NR¹—, —NR¹—CO—NR¹—,—CH═CH—, —C≡C—, —O—CO—O— and —Si(CH₃)₂—O—Si(CH₃)₂—, wherein R¹represents a hydrogen atom or lower alkyl;

[0025] B represents a hydrogen atom, or a group which is able to reactor interact with a second material like polymers, oligomers, monomers,photoactive polymers, photoactive oligomers and/or photoactive monomersor surfaces;

[0026] S₁ and S₂ each independently of the other represent a single bondor a spacer unit such as a straight-chain or branched alkylene groupwhich is unsubstituted, mono or poly-substituted by fluorine, chlorine,having 1 to 40 carbon atoms, wherein one or more non-adjacent —CH₂—groups may independently be replaced by a group D, with the proviso thatoxygen atoms are not directly attached to each other; wherein

[0027] D represents a group selected from —O—, —CO—, —CO—O—, —O—CO—,—NR¹—, —NR¹—CO—, —CO—NR¹—, —NR¹—CO—O—, —O—CO—NR¹—, —NR¹—CO—NR¹—,—CH═CH—, —C≡C—, —O—CO—O— and —Si(CH₃)₂—O—Si(CH₃)₂—, an aromatic or analicyclic group, wherein R¹ represents a hydrogen atom or lower alkyl;

[0028] Q represents an oxygen atom or —NR¹— wherein R¹ represents ahydrogen atom or lower alkyl; and

[0029] X, Y each independently of the other represents hydrogen,fluorine, chlorine, cyano, alkyl optionally substituted by fluorinehaving 1 to 12 carbon atoms in which optionally one or more non-adjacentalkyl —CH₂— groups are replaced by —O—, —CO—O—, —O—CO— and/or —CH═CH—.

[0030] It is preferred that the group A is selected frompyrimidine-2,5-diyl, pyridine-2,5-diyl, 2,5-thiophenylene,2,5-furanylene, 1,4- or 2,6-naphthylene and phenylene, which isunsubstituted or substituted by a cyclic, straight-chain or branchedalkyl residue which is unsubstituted, mono- or poly-substituted byfluorine, chlorine having from 1 to 12 carbon atoms in which optionallyone or more non-adjacent alkyl —CH₂— groups are replaced by —O—, —CO—,—CO—O—, —O—CO—, —CH═CH— and C—C≡C—.

[0031] It is especially preferred that A is selected from2,5-furanylene, 1,4- or 2,6-naphthylene and phenylene, which isunsubstituted or substituted by a cyclic, straight-chain or branchedalkyl residue having 1 to 12 carbon atoms in which optionally one ormore non-adjacent alkyl —CH₂— groups are replaced by —O—, —CO—, —CO—O—,—O—CO—, —CH═H— and —C≡C—.

[0032] By the term “phenylene” it should be understood to include 1,2-,1,3- or 1,4-phenylene, which is optionally substituted. It is preferredthat the phenylene group is either a 1,3- or a 1,4-phenylene.1,4-phenylene groups are especially preferred.

[0033] By the term “group which is able to react or interact with asecond material” it should be understood to include groups likeradically or cationically polymerizable groups; hydrophilic anionicgroups like groups consisting of —OSO₂O⁻, —SO₂O⁻, —CO₂ ⁻, (—O)₂P(O)O⁻,—P(O)(O⁻)₂, —OP(O)(O⁻)₂, —P(O⁻)₂ and —OP(O⁻)₂ in protonated or salt forme.g. as alkali metals salts or ammonium salts; polar groups likealcohol, thiol and isocyanate; and also mono-di-tri-alkoxy or halogenosilanes.

[0034] It is preferred that the group B is selected from hydrogen atom,radically or canonically polymerizable groups or also mono-, di-,tri-alkoxy or halogeno silanes.

[0035] It is more preferred that B is selected form hydrogen atom orradically or cationically polymerizable groups.

[0036] It is especially preferred that B is hydrogen.

[0037] Preferred groups Q are oxygen atom or —NH—.

[0038] It is especially preferred that Q is an oxygen atom.

[0039] It is preferred that the groups X and Y represent hydrogen.

[0040] Preferred photoactive groups are groups of formula Ia.

[0041] It is preferred that the group S₁ is selected from a singlecovalent bond, —O—, —CO—O—, —O—CO—, —NR¹—, —NR¹—CO—, —CO—NR¹—,—NR¹—CO—O—, —O—CO—NR¹—, —NR¹—CO—NR¹—, —CH═CH—, —C≡C—, —O—CO—O— and astraight-chain or branched alkylene group, which is optionallysubstituted by one or more groups selected from fluorine, chlorine andcyano and in which two or three non-adjacent alkylene —CH₂— groups areindependently optionally replaced by a group D with the proviso that thetotal number of chain carbon atoms in the alkylene group does not exceed24, wherein R¹ represents a hydrogen atom or lower alkyl.

[0042] It is more preferred that S₁ is selected from a single covalentbond, —CO—O—, —O—CO—, —(CH₂)_(r), —(CH₂)_(r)—O—, —(CH₂)_(r)—CO—,—(CH₂)_(r)—CO—O—, —(CH₂)_(r)—O—CO—, —(CH₂)_(r)—CO—NR¹—,—(CH₂)_(r)—NR¹—CO—, —(CH₂)_(r)—NR¹—, —O—(CH₂)_(r), —CO—O—(CH₂)_(r),—O—CO—(CH₂)_(r), —NR¹—CO—(CH₂)_(r), —CO—NR¹—(CH₂)_(r), —NR¹—(CH₂)_(r),—O—(CH₂)_(r)—CO—O—, —O—(CH₂)_(r)—O—CO—, —O—(CH₂)_(r)—CO—NR¹—,—O—(CH₂)_(r)—NR¹—, —O—(CH₂)_(r)—O—, —O—(CH₂)_(r)—NR¹—CO—,—NR¹—(CH₂)_(r)—CO—O—, —NR¹—(CH₂)_(r)—O—, —NR¹—(CH₂)_(r)—NR¹—,—NR¹—(CH₂)_(r)—O—CO—, —CO—NR¹—(CH₂)_(r)—O—, —CO—NR¹—(CH₂)_(r)—NR¹—,—CO—NR¹—(CH₂)_(r)—O—CO—, —O—CO—(CH₂)_(r)—CO—, —O—CO—(CH₂)_(r)—O—,—O—CO—(CH₂)_(r)—NR²—, —O—CO—(CH₂)_(r)—CO—O—, —O—CO—(CH₂)_(r)—CO—NR¹—,—O—CO—(CH₂)_(r)—NR¹—CO—, —(CH₂)_(r)—O—(CH₂)_(s)—,(CH₂)_(r)—CO—O—(CH₂)_(s)—, —(CH₂)_(r)—O—CO—(CH₂)_(s)—,—(CH₂)_(r)—NR¹—CO—(CH₂)_(s)—, —(CH₂)_(r)—NR¹—CO—O—(CH₂)_(s)—,—(CH₂)_(r)—O—(CH₂)_(s)—O—, —(CH₂)_(r)—CO—O—(CH₂)_(s)—O—,—(CH₂)_(r)—O—CO—(CH₂)_(s)—O—, —(CH₂)_(r)—NR¹—CO—(CH₂)_(s)—O—,—(CH₂)_(r)—NR¹—CO—O—(CH₂)_(s)—O—, —O—(CH₂)_(r)—O—(CH₂)_(s)—,—O—(CH₂)_(r)—CO—O—(CH₂)_(s)—, —O—(CH₂)_(r)—NR¹—CO—(CH₂)_(s)—,—O—(CH₂)_(r)—NR¹—CO—O—(CH₂)_(s)—, —O—(CH₂)_(r)—CO—O—(CH₂)_(s)—O—,—O—(CH₂)_(r)—O—(CH₂)_(s)—O—, —O—(CH₂)_(r)—NR¹—CO—(CH₂)_(s)—O—,—O—(CH₂)_(r)—NR¹—CO—O—(CH₂)_(s)—O—, —CO—O—(CH₂)_(r)—O—(CH₂)_(s)— and—CO—O—(CH₂)_(r)—O—(CH₂)_(s)—O—, wherein R¹ is as defined above, r and seach represent an integer from 1 to 20, preferably from 1 to 12, andr+s≦21, preferably ≦15.

[0043] By the terms —(CH₂)_(r)— and —(CH₂)_(s)— it should be understoodto include straight-chain or branched alkylene groupings containing r ors carbon atoms respectively.

[0044] It is especially preferred that S₁ is selected from a singlecovalent bond, —(CH₂)_(r)—, —(CH₂)_(r)—O—, —(CH₂)_(r)—CO—O—,—(CH₂)_(r)—O—CO—, —(CH₂)_(r)—CO—NH—, —(CH₂)_(r)—NH—CO—, —O—(CH₂)_(r),—CO—O—(CH₂)_(r), —CO—NH—(CH₂)_(r), —O—CO—(CH₂)_(r), —O—COCH₂)_(r)—CO—O—,—O—(CH₂)_(r)—O—CO—, —O(CH₂)_(r)—CO—NH—, —O—(CH₂)_(r)—NH—CO—,—CO—O—(CH₂)_(r)—O—, —CO—NH—(CH₂)_(r)—O—, —O—(CH₂))_(r)—O—,(CH₂)_(r)—NH—CO—(CH₂)_(s)—, —(CH₂)_(r)—NH—CO—O—(CH₂)_(s)—,—(CH₂)_(r)—O—(CH₂)_(s)—O—, —(CH₂)_(r)—NH—CO—(CH₂)_(s)—O—,—(CH₂)_(r)—NHCO—O—(CH₂)_(s)—O—, —O—(CH₂)_(r)—NH—CO—(CH₂)_(s)—,—O—(CH₂)_(r)—O—(CH₂)_(s)—O—, —O—CO—(CH₂)_(r)—O—(CH₂)_(s)—O—,—CO—O—(CH₂)_(r)—O—(CH₂)_(s)—O—, —O—(CH₂)_(r)—NH—CO—(CH₂)_(s)—O— and—O—CO—(CH₂)_(r)—NH—CO—(CH₂)_(s)—O—, wherein r and s each represent aninteger from 1 to 12 and r+s≦15.

[0045] Examples of preferred groups S₁ include 1,2-ethylene,1,3-propylene, 1,4-butylene, 1,5-pentylene, 1,6-hexylene, 1,7-heptylene,1,8-octylene, 1,9-nonylene, 1,10-decylene, 1,11-undecylene,1,12-dodecylene, 3-methyl-1,4-butylene, 3-propyleneoxy,3-propyleneoxycarbonyl, 2-ethylenecarbonyloxy, 4-butyleneoxy,4-butyleneoxycarbonyl, 3-propylenecarbonyloxy, 5-pentyleneoxy,5-pentyleneoxycarbonyl, 4-butylenecarbonyloxy, 6-hexyleneoxy,6-hexyleneoxycarbonyl, 5-pentylenecarbonyloxy, 7-heptyleneoxy,7-heptyleneoxycarbonyl, 6-hexylenecarbonyloxy, 8-octyleneoxy,8-octyleneoxycarbonyl, 7-heptylenecarbonyloxy, 9-nonyleneoxy,9-nonyleneoxycarbonyl, 8-6-otylenecarbonyloxy, 10-decyleneoxy,10-decyleneoxycarbonyl, 9-nonylenecarbonyloxy, 11-undecyleneoxy,11-undecyleneoxycarbonyl, 10-decylenecarbonyloxy, 12-dodecyleneoxy,12-dodecyleneoxycarbonyl, 1-undecylenecarbonyloxy,3-propyleneiminocarbonyl, 4-butyleneiminocarbonyl,5-pentyleneiminocarbonyl, 6-hexyleneiminocarbonyl,7-heptyleneiminocarbonyl, 8-octyleneiminocarbonyl,9-nonyleneiminocarbonyl, 10-decyleneiminocarbonyl,11-undecyleneiminocarbonyl, 12-dodecyleneiminocarbonyl,2-ethylenecarbonylimino, 3-propylenecarbonylimino,4-butylenecarbonylimino, 5-pentylenecarbonylimino,6-hexylenecarbonylimino, 7-heptylenecarbonylimino,8-octylenecarbonylimino, 9-nonylenecarbonylimino,10-decylenecarbonylimino, 11-undecylenecarbonylimino,6-(3-propyleneiminocarbonyloxy)hexylene, 6-(3-propyleneoxy)hexylene,6-(3-propyleneoxy)hexyloxy, 6-(3-propyleneiminocarbonyloxy)hexyloxy,6-(3-propyleneiminocarbonyl)hexyl, 6-(3-propyleneiminocarbonyl)hexyloxy,1,2-ethylenedioxy, 1,3-propylenedioxy, 1,4-butylenedioxy,1,5-pentylenedioxy, 1,6-hexylenedioxy, 1,7-heptylenedioxy,1,8-octylenedioxy, 1,9-nonylenedioxy, 1,10-decylenedioxy,1,11-undecylenedioxy, 1,12-dodecylenedioxy and the like.

[0046] It is preferred that the group S₂ is selected from a singlecovalent bond, a straight-chain or branched alkylene group, which isoptionally substituted by one or more groups selected from fluorine,chlorine and cyano and in which two or three non-adjacent alkylene —CH₂—groups are independently optionally replaced by a group D with theproviso that the total number of chain carbon atoms in the alkylenegroup does not exceed 24, wherein R¹ represents a hydrogen atom or loweralkyl.

[0047] It is especially preferred that S₂ is selected from a singlecovalent bond, —(CH₂)_(r), —(CH₂)_(r)—O—, (CH₂)_(r)—CO—,—(CH₂)_(r)—CO—O—, —(CH₂)_(r)—O—CO—, —(CH₂)_(r)—CO—NR¹—(CH₂)_(r)—NR¹—CO—,—(CH₂)_(r)—NR¹—, —(CH₂)_(r)—O—(CH₂)_(s)—, —(CH₂)_(r)—CO—O—(CH₂)_(s)—,—(CH₂)_(r)—O—CO—(CH₂)_(s)—, —(CH₂)_(r)—NR¹—CO—(CH₂)_(s)—,—(CH₂)_(r)—NR¹—CO—O—(CH₂)_(s)—, —(CH₂)_(r)—O—(CH₂)_(s)—O—,—(CH₂)_(r)—CO—O—(CH₂)_(s)—O—, —(CH₂)_(r)—O—CO—(CH₂)_(s)—O—,—(CH₂)_(r)—NR¹—CO—(CH₂)_(s)—O—, —(CH₂)_(r)—NR¹—CO—O—(CH₂)_(s)—O—,—(CH₂)_(r)(CH₂)_(s)—CO—O— and —(CH₂)_(r)—O—(CH₂)_(s)—O—CO—, wherein R¹is as defined herein above; r and s each represent an integer from 1 to20; and r+s≦21. It is more preferred that r and s each represent aninteger from 1 to 12. It is especially preferred that r+s≦15.

[0048] Examples of preferred groups S₂ include 1,2-ethylene,1,3-propylene, 1,4-butylene, 1,5-pentylene, 1,6-hexylene, 1,7-heptylene,1,8-octylene, 1,9-nonylene, 1,10-decylene, 1,11-undecylene,1,12-dodecylene, 3-methyl-1,4-butylene, 3-propyleneoxy,3-propyleneoxycarbonyl, 2-ethylenecarbonyloxy, 4-butyleneoxy,4-butyleneoxycarbonyl, 3-propylenecarbonyloxy, 5-pentyleneoxy,5-pentyleneoxycarbonyl, 4-butylenecarbonyloxy, 6-hexyleneoxy,6-hexyleneoxycarbonyl, 5-pentylenecarbonyloxy, 7-heptyleneoxy,7-heptyleneoxycarbonyl, 6-hexylenecarbonyloxy, 8-octyleneoxy,8-octyleneoxycarbonyl, 7-heptylenecarbonyloxy, 9-nonyleneoxy,9-nonyleneoxycarbonyl, 8-octylenecarbonyloxy, 10-decyleneoxy,10-decyleneoxycarbonyl, 9-nonylenecarbonyloxy, 11-undecyleneoxy,11-undecyleneoxycarbonyl, 10-decylenecarbonyloxy, 12-dodecyleneoxy,12-dodecyleneoxycarbonyl, 11-undecylenecarbonyloxy,3-propyleneiminocarbonyl, 4-butyleneiminocarbonyl,5-pentyleneiminocarbonyl, 6-hexyleneiminocarbonyl,7-heptyleneiminocarbonyl, 8-octyleneiminocarbonyl,9-nonyleneiminocarbonyl, 10-decyleneiminocarbonyl,11-undecyleneiminocarbonyl, 12-dodecyleneiminocarbonyl,2-ethylenecarbonylimino, 3-propylenecarbonylimino,4-butylenecarbonylimino, 5-pentylenecarbonylimino,6-hexylenecarbonylimino, 7-heptylenecarbonylimino,8-octylenecarbonylimino, 9-nonylenecarbonylimino,10-decylenecarbonylimino, 11-undecylenecarbonylimino,6-(3-propyleneiminocarbonyloxy)hexylene, 6-(3-propyleneoxy)hexylene,6-(3-propyleneoxy)hexyloxy, 6-(3-propyleneiminocarbonyloxy)hexyloxy,6-(3-propyleneiminocarbonyl)hexylene,6-(3-propyleneiminocarbonyl)hexyloxy and the like.

[0049] By the term “aromatic” it should be understood to includeoptionally substituted carbocylic and heterocyclic groups incorporatingfive, six or ten ring atoms like furan, phenyl, pyridine, pyrimidine,naphthalene, or tetraline units.

[0050] By the term “cyclic, straight-chain or branched alkyl residuewhich is unsubstituted, mono-substituted by cyano or fluorine, chlorine,or poly-substituted by fluorine, chlorine, having 1 to 18 carbon atoms,wherein one or more non-adjacent-CH₂— groups may independently bereplaced by a group C,” it should be understood to include groupsselected from the group comprising methyl, ethyl, propyl, isopropyl,butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, cyclopentyl,hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl,3-methylpentyl, allyl, but-3-en-1-yl, pent-4-en-1-yl, hex-5-en-1-yl,propynyl, butynyl, pentynyl, methoxy, ethoxy, propoxy, isopropoxy,butoxy, isobutoxy, sec-butoxy, tert-butoxy, pentyloxy, isopentyloxy,cyclopentyloxy, hexyloxy, cyclohexyloxy, heptyloxy, octyloxy, nonyloxy,decyloxy, undecyloxy, dodecyloxy, 3-methylpentyloxy, allyloxy,but-3-enyloxy, pent-4-enyloxy, cylohexylmethoxy, cyclopentylmethoxy,methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl,butoxycarbonyl, isobutoxycarbonyl, sec-butoxycarbonyl,tert-butoxycarbonyl, pentyloxycarbonyl, isopentyloxycarbonyl,cyclopentyloxycarbonyl, hexyloxycarbonyl, cyclohexyloxycarbonyl,octyloxycarbonyl, nonyloxycarbonyl, decyloxycarbonyl,undecyloxycarbonyl, dodecyloxycarbonyl, 3-methylpentyloxycarbonyl,allyloxycarbonyl, but-3-enyloxycarbonyl, pent-4-enyloxycarbonyl,cylohexylmethoxycarbonyl, cyclopentylmethoxycarbonyl, acetoxy,ethylcarbonyloxy, propylcarbonyloxy, isopropylcarbonyloxy,butyl-carbonyloxy, isobutylcarbonyloxy, sec-butylcarbonyloxy,tert-butylcarbonyloxy, pentylcarbonyloxy, isopentylcarbonyloxy,cyclopentylcarbonyloxy, 4-[3,4,5-tris(octyloxy)benzyl]oxy,hexylcarbonyloxy, cyclohexylcarbonyloxy, (4-propylcyclohexyl)methoxy,(4-propylcyclohexyl)carbonyloxy, (4-pentylbenzoyl)oxy, octylcarbonyloxy,nonylcarbonyloxy, decylcarbonyloxy, undecylcarbonyloxy,dodecyl-carbonyloxy, 3-methylpentylcarbonyloxy, but-3-enyloxy,pent-4-enyloxy, acetyl, ethyl-carbonyl, propylcarbonyl,isopropylcarbonyl, butylcarbonyl, isobutylcarbonyl, sec-butylcarbonyl,pentylcarbonyl, isopentylcarbonyl, cyclohexylcarbonyl, octyl-carbonyl,nonylcarbonyl, decylcarbonyl, undecylcarbonyl, dodecylcarbonyl,methoxyacetoxy, 1-methoxy-2-propoxy, 3-methoxy-1-propoxy,2-methoxyethoxy, 2-isopropoxyethoxy, 1-ethoxy-3-pentyloxy, 3-butynyloxy,4-pentynyloxy, 5-chloropentynyl, 4-pentynecarbonyloxy, 6-propyloxyhexyl,6-propyloxyhexyloxy, 2-fluoroethyl, trifluoromethyl,2,2,2-trifluoroethyl, 1H,1H-pentadecafluorooctyl,1H,1H,7H-dodecafluoroheptyl, 2-(perfluorooctyl)ethyl,2-(perfluorobutyl)ethyl, 2-(perfluorohexyl)ethyl,2-(perfluorodecyl)ethyl, perfluoropropyl, perfluorobutyl,perfluoroheptyl, perfluorooctyl, perfluorononyl, 1-fluoropropoxy,1-fluoropentyloxy, 2-fluoropropoxy, 2,2-difluoropropoxy,3-fluoropropoxy, 3,3-difluoropropoxy, 3,3,3-trifluoropropoxy,trifluoromethoxy and the like.

[0051] By the term “straight-chain or branched alkylene residue which isunsubstituted, mono-substituted by cyano or fluorine, chlorine, orpoly-substituted by fluorine, chlorine, having 1 to 40 carbon atoms,wherein one or more non-adjacent —CH₂— groups may independently bereplaced by a group D,” it should be understood to include groupsselected from the group comprising 1,2-ethylene, 1,3-propylene,1,4-butylene, 1,5-pentylene, 1,6-hexylene, 1,7-heptylene, 1,8-octylene,1,9-nonylene, 1,10-decylene, 1,11-undecylene, 1,12-dodecylene,3-methyl-1,4-butylene, 3-propyleneoxy, 3-propyleneoxycarbonyl,2-ethylenecarbonyloxy, 4-butyleneoxy, 4-butyleneoxycarbonyl,3-propylenecarbonyloxy, 5-pentyleneoxy, 5-pentyleneoxycarbonyl,4-butylenecarbonyloxy, 6-hexyleneoxy, 6-hexyleneoxycarbonyl,5-pentylenecarbonyloxy, 7-heptyleneoxy, 7-heptyleneoxycarbonyl,6-hexylenecarbonyloxy, 8-octyleneoxy, 8-octyleneoxycarbonyl,7-heptylenecarbonyloxy, 9-nonyleneoxy, 9-nonyleneoxycarbonyl,8-octylenecarbonyloxy, 10-decyleneoxy, 10-decyleneoxycarbonyl,9-nonylenecarbonyloxy, 11-undecyleneoxy, 11-undecyleneoxycarbonyl,10-decylenecarbonyloxy, 12-dodecyleneoxy, 12-dodecyleneoxycarbonyl,11-undecylenecarbonyloxy, 3-propyleneiminocarbonyl,4-butyleneiminocarbonyl, 5-pentyleneiminocarbonyl,6-hexyleneiminocarbonyl, 7-heptyleneiminocarbonyl,8-octyleneiminocarbonyl, 9-nonyleneiminocarbonyl,10-decyleneiminocarbonyl, 11-undecyleneiminocarbonyl,12-dodecyleneiminocarbonyl, 2-ethylenecarbonylimino,3-propylenecarbonylimino, 4-butylenecarbonylimino,5-pentylenecarbonylimino, 6-hexylenecarbonylimino,7-heptylenecarbonylimino, 8-octylenecarbonylimino,9-nonylenecarbonylimino, 10-decylenecarbonylimino,111-undecylenecarbonylimino, 6-(3-propyleneiminocarbonyloxy)hexylene,6-(3-propyleneoxy)hexylene, 6-(3-propyleneoxy)hexyloxy,6-(3-propyleneiminocarbonyloxy)hexyloxy,6-(3-propyleneiminocarbonyl)hexyl, 6-(3-propyleneiminocarbonyl)hexyloxy,1,2-ethylenedioxy, 1,3-propylenedioxy, 1,4-butylenedioxy,1,5-pentylenedioxy, 1,6-hexylenedioxy, 1,7-heptylenedioxy,1,8-octylenedioxy, 1,9-nonylenedioxy, 1,10-decylenedioxy,1,11-undecylenedioxy, 1,12-dodecylenedioxy,2-{4-[4-(2-oxy-ethyl)cyclohexyl]phenyl}ethoxy,2-[4′-(4-oxybutyl)-1,1′biphenyl-4-yl]ethoxy,2-{4-[4-(2-oxy-ethyl)phenyl}ethoxy,2-{4-[4-(2-carbonyloxyethyl)cyclohexyl]phenyl}-ethoxy,2-[4′-(4-carbonyloxybutyl)-1,1′biphenylene-4-yl]ethoxy,6-{4-[4-(2-carbonyloxyethyl)phenyl}hexyloxy,5-{[4′-(4-oxybutoxy)-1,1′-biphenyl-4-yl]oxy}pentylcarbonyloxy,2-oxyethylene, 3-oxypropylene, 4-oxybutylene, 5-oxypentylene,6-oxyhexylene, 7-oxyheptylene, 8-oxyoctylene, 9-oxynonylene,10-oxydecylene, 11-oxyundecylene, 12-oxydodecylene,2-(oxycarbonyl)ethylene, 3-(oxycarbonyl)propylene,4-(oxycarbonyl)butylene, 5-(oxycarbonyl)pentylene,6-(oxycarbonyl)hexylene, 7-(oxycarbonyl)heptylene,8-(oxycarbonyl)octylene, 9-(oxycarbonyl)nonylene,10-(oxycarbonyl)decylene, 11-(oxycarbonyl)undecylene,12-(oxycarbonyl)dodecylene, 2-(carbonyloxy)ethylene,3-(carbonyloxy)propylene, 4-(carbonyloxy)butylene,5-(carbonyloxy)pentylene, 6-(carbonyloxy)hexylene,7-(carbonyloxy)-heptylene, 8-(carbonyloxy)octylene,9-(carbonyloxy)nonylene, 10-(carbonyloxy)-decylene,11-(carbonyloxy)undecylene, 12-(carbonyloxy)dodecylene,2-(carbonylimino)ethylene, 3-(carbonylimino)propylene,4-(carbonylimino)butylene, 5-(carbonylimino)pentylene,6-(carbonylimino)hexylene, 7-(carbonylimino)heptylene,8-(carbonylimino)octylene, 9-(carbonylimino)nonylene,10-(carbonylimino)decylene, 11-(carbonylimino)undecylene,12-(carbonylimino)dodecylene, 2-iminoethylene, 3-iminopropylene,4-iminobutylene, 5-iminopentylene, 6-iminohexylene, 7-iminoheptylene,8-iminooctylene, 9-iminononylene, 10-iminodecylene, 11-iminoundecylene,12-iminododecylene, 2-iminocarbonylethylene, 3-iminocarbonylpropylene,4-iminocarbonylbutylene, 5-iminocarbonylpentylene,6-iminocarbonylhexylene, 7-iminocarbonylheptylene,8-iminocarbonyloctylene, 9-iminocarbonylnonylene,10-iminocarbonyldecylene, 11-iminocarbonylundecylene,12-iminocarbonyldodecylene, 2-(2-ethyleneoxy)ethylene,2-(3-propyleneoxy)ethylene, 6-(4-butyleneoxy)hexylene,2-(2-ethyleneiminocarbonyl)ethylene,2-(3-propyleneiminocarbonyl)ethylene,6-(4-butyleneiminocarbonyl)hexylene,6-(3-propyleneiminocarbonyloxy)hexylene,6-(3-propyleneiminocarbonyl)hexylene and the like.

[0052] By the term “lower alkyl” it should be understood to includestraight chain and branched hydrocarbon radicals having from 1 to 6carbon atoms, preferably from 1 to 3 carbon atoms. Methyl, ethyl, propyland isopropyl groups are especially preferred.

[0053] By the term “alicyclic” it should be understood to includenon-aromatic carbocyclic or heterocyclic ring systems with 3 to 10carbon atoms like cyclopropane, cyclobutane, cyclopentane, cyclopentene,cyclohexane, cyclohexene, cyclohexadiene and decaline.

[0054] By the term “radically or cationically polymerizable group” itshould be understood to include preferably acrylate, methacrylate,2-chloroacrylate, 2 phenylacrylate; N-lower alkyl substitutedacrylamide, methacrylamide, 2-chloroacrylamide and 2-phenacrylamide;vinyl ether, vinyl ester, styrene derivative; maleic acid derivative;fumaric acid derivative; cinnamate derivative and epoxy derivative andthe like. Preferred groups are acrylate, methacrylate; N-lower alkylsubstituted acrylamide, vinyl ether, vinyl ester, styrene derivative;maleic acid derivative and cinnamate derivative. Most preferred groupsare acrylate, methacrylate, vinyl ether and cinnamate derivative.

[0055] The terminal moieties can also be hydrogen; or a group like groupB which is able to react or interact with a second material likepolymers, oligomers, monomers, photoactive polymers, photoactiveoligomers and/or photoactive monomers or surfaces; or an unit such as astraight-chain or branched alkyl group which is unsubstituted, mono orpoly-substituted by fluorine, chlorine, cyano, having 1 to 24 carbonatoms, wherein one or more —CH₂— groups may independently be replaced bya group D, with the proviso that oxygen atoms are not directly attachedto each other.

[0056] Preferred is that at least four terminal moieties are photoactivegroups.

[0057] The repeating branching units refers to a constituent portionconnecting one core portion or a branching portion to a adjacentbranching portion or an adjacent terminal portion. The structure of therepeat branching units is not specially limited. Each repeat branchingunit of a dendrimer are not necessarily the same. Further, the number ofbranching units per dendrimer use in the present invention is at least 3i.e. four terminal groups and containing at least four photoreactivegroups.

[0058] Preferred branching units are represented by dendritic blocks ofthe general formulae IIa, IIb or a combination of them, for exampleformula IIc:

[0059] wherein

[0060] the broken line indicates the point of linkage to the coreportion or to the Z units of the previous generation of branching units;and

[0061] the full line indicates the point of linkage to the E residue ofthe next generation of branching units or the point of linkage to theterminal groups; and wherein

[0062] E represents an organic residue;

[0063] Z represents a single bond or a spacer unit such as astraight-chain or branched alkylene group which is unsubstituted, monoor poly-substituted by fluorine, chlorine, having 1 to 24 carbon atoms,wherein one or more —CH₂— groups may independently be replaced by agroup D, with the proviso that oxygen atoms are not directly attached toeach other, or Z may also represent a photoreactive group like groupsrepresented by general formula Ia and Ib wherein B in this caseindicates the point of linkage to E and wherein A, S₁, S₂, Q, X and Yare as defined above.

[0064] Especially preferred branching units are groups of formula IIaand groups of formula IIc, while groups of formula IIb, if present, arefavorably located in the outermost generation.

[0065] Most preferred dendritic blocks are groups of formulae Ia.

[0066] It is also preferred that the groups E are aromatic, alicyclic orCR¹— units wherein R¹ has the meaning defined above.

[0067] It is especially preferred that the groups E are selected form1,2,3-benzenetriyl, 1,3,4-benzenetriyl, 1,3,5-benzenetriyl or a groupCR¹—.

[0068] It is preferred that the group Z is selected from a singlecovalent bond, —O—, —CO—O—, —O—CO—, —NR¹—, —NR¹—CO—, —CO—NR¹—,—NR¹—CO—O—, —O—CO—NR¹—, —NR¹—CO—NR¹—, —CH═CH—, —C≡C—, —O—CO—O— and astraight-chain or branched alkylene group, which is optionallysubstituted by one or more groups selected from fluorine, chlorine andcyano and in which one up to four non-adjacent alkylene —CH₂— groups areindependently optionally replaced by a group D with the proviso that thetotal number of chain carbon atoms in the alkylene group does not exceed30 and wherein R¹ represents a hydrogen atom or lower alkyl.

[0069] It is also preferred that Z represents photoreactive groups likegroups represented by general formula Ia and Ib wherein B in this caseindicates the point of linkage to E and wherein A, S₁, S₂, Q, X and Yare as defined above.

[0070] Examples for preferred groups Z include 1,2-ethylene,1,3-propylene, 1,4-butylene, 1,5-pentylene, 1,6-hexylene, 1,7-heptylene,1,8-octylene, 1,9-nonylene, 1,10-decylene, 1,11-undecylene,1,12-dodecylene, 3-methyl-1,4-butylene, 3-propyleneoxy,3-propyleneoxycarbonyl, 2-ethylenecarbonyloxy, 4-butyleneoxy,4-butyleneoxycarbonyl, 3-propylenecarbonyloxy, 5-pentyleneoxy,5-pentyleneoxycarbonyl, 4-butylenecarbonyloxy, 6-hexyleneoxy,6-hexyleneoxycarbonyl, 5-pentylenecarbonyloxy, 7-heptyleneoxy,7-heptyleneoxycarbonyl, 6-hexylenecarbonyloxy, 8-octyleneoxy,8-octyleneoxycarbonyl, 7-heptylenecarbonyloxy, 9-nonyleneoxy,9-nonyleneoxycarbonyl, 8-octylenecarbonyloxy, 10-decyleneoxy,10-decyleneoxycarbonyl, 9-nonylenecarbonyloxy, 11-undecyleneoxy,11-undecyleneoxycarbonyl, 10-decylenecarbonyloxy, 12-dodecyleneoxy,12-dodecyleneoxycarbonyl, 1-undecylenecarbonyloxy,3-propyleneiminocarbonyl, 4-butyleneiminocarbonyl,5-pentyleneiminocarbonyl, 6-hexyleneiminocarbonyl,7-heptyleneiminocarbonyl, 8-octyleneiminocarbonyl,9-nonyleneiminocarbonyl, 10-decyleneiminocarbonyl,11-undecyleneiminocarbonyl, 12-dodecyleneiminocarbonyl,2-ethylenecarbonylimino, 3-propylenecarbonylimino,4-butylenecarbonylimino, 5-pentylenecarbonylimino,6-hexylenecarbonylimino, 7-heptylenecarbonylimino,8-octylenecarbonylimino, 9-nonylenecarbonylimino,10-decylenecarbonylimino, 11-undecylenecarbonylimino,6-(3-propyleneiminocarbonyloxy)hexylene, 6-(3-propyleneoxy)hexylene,6-(3-propyleneoxy)hexyloxy, 6-(3-propyleneiminocarbonyloxy)hexyloxy,6-(3-propyleneiminocarbonyl)hexyl, 6-(3-propyleneiminocarbonyl)hexyloxy,1,2-ethylenedioxy, 1,3-propylenedioxy, 1,4-butylenedioxy,1,5-pentylenedioxy, 1,6-hexylenedioxy, 1,7-heptylenedioxy,1,8-octylenedioxy, 1,9-nonylenedioxy, 1,10-decylenedioxy,1,11-undecylenedioxy, 1,12-dodecylenedioxy,2-{4-[4-(2-oxy-ethyl)cyclohexyl]phenyl}ethoxy,2-[4′-(4-oxybutyl)-1,1′biphenyl-4-yl]ethoxy,2-{4-[4-(2-oxy-ethyl)phenyl}ethoxy,2-{4-[4-(2-carbonyloxyethyl)cyclohexyl]phenyl}-ethoxy,2-[4′-(4-carbonyloxybutyl)-1,1′biphenylene-4-yl]ethoxy,6-{4-[4-(2-carbonyloxyethyl)phenyl}hexyloxy,5-{[4′-(4-oxybutoxy)-1,1′-biphenyl-4-yl]oxy}pentylcarbonyloxy,2-oxyethylene, 3-oxypropylene, 4-oxybutylene, 5-oxypentylene,6-oxyhexylene, 7-oxyheptylene, 8-oxyoctylene, 9-oxynonylene,10-oxydecylene, 11-oxyundecylene, 12-oxydodecylene,2-(oxycarbonyl)ethylene, 3-(oxycarbonyl)propylene,4-(oxycarbonyl)butylene, 5-(oxycarbonyl)pentylene,6-(oxycarbonyl)hexylene, 7-(oxycarbonyl)heptylene,8-(oxycarbonyl)octylene, 9-(oxycarbonyl)nonylene,10-(oxycarbonyl)decylene, 11-(oxycarbonyl)undecylene,12-(oxycarbonyl)dodecylene, 2-(carbonyloxy)ethylene,3-(carbonyloxy)propylene, 4-(carbonyloxy)butylene,5-(carbonyloxy)pentylene, 6-(carbonyloxy)hexylene,7-(carbonyloxy)-heptylene, 8-(carbonyloxy)octylene,9-(carbonyloxy)nonylene, 10-(carbonyloxy)-decylene,11-(carbonyloxy)undecylene, 12-(carbonyloxy)dodecylene,2-(carbonylimino)ethylene, 3-(carbonylimino)propylene,4-(carbonylimino)butylene, 5-(carbonylimino)pentylene,6-(carbonylimino)hexylene, 7-(carbonylimino)heptylene,8-(carbonylimino)octylene, 9-(carbonylimino)nonylene,10-(carbonylimino)decylene, 11-(carbonylimino)undecylene,12-(carbonylimino)dodecylene, 2-iminoethylene, 3-iminopropylene,4-iminobutylene, 5-iminopentylene, 6-iminohexylene, 7-iminoheptylene,8-iminooctylene, 9-iminononylene, 10-iminodecylene, 11-iminoundecylene,12-iminododecylene, 2-iminocarbonylethylene, 3-iminocarbonylpropylene,4-iminocarbonylbutylene, 5-iminocarbonylpentylene,6-iminocarbonylhexylene, 7-iminocarbonylheptylene,8-iminocarbonyloctylene, 9-iminocarbonylnonylene,10-iminocarbonyldecylene, 11-iminocarbonylundecylene,12-iminocarbonyldodecylene, 2-(2-ethyleneoxy)ethylene,2-(3-propyleneoxy)ethylene, 6-(4-butyleneoxy)hexylene,2-(2-ethyleneiminocarbonyl)ethylene,2-(3-propyleneiminocarbonyl)ethylene,6-(4-butyleneiminocarbonyl)hexylene,6-(3-propyleneiminocarbonyloxy)hexylene,6-(3-propyleneiminocarbonyl)hexylene,6-oxyhexyl(2E)-3-[4-(4-oxybutoxy)-3-methoxyphenyl]-2-propenoate,8-oxyoctyl(2E)-3-[4-(5-oxypentoxy)phenyl]-2-propenoate,6-oxyhexyl(2E)-3-[4-(4-(carbonyloxy)butoxy)-3-methoxyphenyl]-2-propenoate,8-(oxycarbonyl)octyl(2E)-3-[4-(5-oxypentoxy)phenyl]-2-propenoate and thelike.

[0071] The core portions (FIG. 1) of the present invention are notlimited. They can be covalently bonded to one, two, three or fourdendritic units. Preferred core units are represented by formulae IIIa,IIIb, IIIc, IIId and IIIe:

[0072] wherein the broken line indicates the point of linkage with abranching unit and wherein

[0073] F represents a single bond or a unit such as a straight-chain orbranched alkylene group which is unsubstituted, mono or poly-substitutedby fluorine, chlorine, having 1 to 40 carbon atoms, wherein one or more—CH₂— groups may independently be replaced by a group D, with theproviso that oxygen atoms are not directly attached to each other, or Frepresents a photoreactive group like groups represented by generalformula Ia and Ib wherein B in this case indicates the point of linkageto the first generation of the dendrimer;

[0074] G represents a hydrogen atom; a group which is able to react orinteract with a second material like polymers, oligomers, monomers,photoactive polymers, photoactive oligomers and/or photoactive monomersor surfaces; or a monomer repeating unit in a homo or copolymer from aradical or cationic polymerisation;

[0075] K represents a nitrogen atom, a carbon atom, a group CR¹— or anaromatic or alicyclic group, which is optionally substituted by a groupselected from fluorine, chlorine, cyano and a C₁₋₁₈ cyclic,straight-chain or branched alkyl group, which is optionally substitutedby a single cyano group or by one or more halogen atoms and in which oneor more non-adjacent alkyl —CH₂— groups are optionally replaced by agroup selected from —O—, —CO—, —CO—O—, —O—CO—, —Si(CH₃)₂—O—Si(CH₃)₂—,—NR¹—, —NR¹—CO—, —CO—NR¹—, —NR¹—CO—O—, —O—CO—NR¹—, —NR¹—CO—NR¹—,—CH═CH—, —C≡C— and —O—CO—O—, wherein R¹ represents a hydrogen atom orlower alkyl; and

[0076] J represents a carbon atom or an aromatic or alicyclic group,which is optionally substituted by a group selected from fluorine,chlorine, cyano and a C₁₋₁₈ cyclic, straight-chain or branched alkylgroup, which is optionally substituted by a single cyano group or by oneor more halogen atoms and in which one or more non-adjacent alkyl —CH₂—groups are optionally replaced by a group selected from —O—, —CO—,—CO—O—, —O—CO—, —Si(CH₃)₂—O—Si(CH₃)₂—, —NR¹—, —NR¹—CO—, —CO—NR¹—,—NR¹—CO—O—, —O—CO—NR¹—, —NR¹—CO—NR¹—, —CH═CH—, —C≡C— and —O—CO—O—,wherein R¹ represents a hydrogen atom or lower alkyl.

[0077] By the term “a monomer repeating unit in a homo or copolymer froma radical or cationic polymerisation” it should be understood to includemonomer repeating unit form the group acrylate, methacrylate,2-chloroacrylate, 2 phenylacrylate; N-lower alkyl substitutedacrylamide, methacrylamide, 2-chloroacrylamide and 2-phenacrylamide;vinyl ether, vinyl ester, styrene derivative; maleic acid derivative;fumaric acid derivative; cinnamate derivative and epoxy derivative andthe like.

[0078] It is preferred that the group F is selected from a singlecovalent bond, —O—, —CO—O—, —O—CO—, —NR¹—, —NR¹—CO—, —CO—NR¹—,—NR¹—CO—O—, —O—CO—NR¹—, —NR¹—CO—NR¹—, —CH═CH—, —C≡C—, —O—CO—O— and astraight-chain or branched alkylene group, which is optionallysubstituted by one or more groups selected from fluorine, chlorine andcyano and in which up to four non-adjacent alkylene —CH₂— groups areindependently optionally replaced by a group D with the proviso that thetotal number of chain carbon atoms in the alkylene group does not exceed30, wherein R¹ represents a hydrogen atom or lower alkyl.

[0079] It is also preferred that F represents photoreactive groups likea group represented by general formula Ia or Ib wherein B in this caseindicates the point of linkage to the first dendron generation andwherein A, S₁, S₂, Q, X and Y areas defined above.

[0080] Example for preferred groups F include 1,2-ethylene,1,3-propylene, 1,4-butylene, 1,5-pentylene, 1,6-hexylene, 1,7-heptylene,1,8-octylene, 1,9-nonylene, 1,10-decylene, 1,11-undecylene,1,12-dodecylene, 3-methyl-1,4-butylene, 3-propyleneoxy,3-propyleneoxycarbonyl, 2-ethylenecarbonyloxy, 4-butyleneoxy,4-butyleneoxycarbonyl, 3-propylenecarbonyloxy, 5-pentyleneoxy,5-pentyleneoxycarbonyl, 4-butylenecarbonyloxy, 6-hexyleneoxy,6-hexyleneoxycarbonyl, 5-pentylenecarbonyloxy, 7-heptyleneoxy,7-heptyleneoxycarbonyl, 6-hexylenecarbonyloxy, 8-octyleneoxy,8-octyleneoxycarbonyl, 7-heptylenecarbonyloxy, 9-nonyleneoxy,9-nonyleneoxycarbonyl, 8-octylenecarbonyloxy, 10-decyleneoxy,10-decyleneoxycarbonyl, 9-nonylenecarbonyloxy, 11-undecyleneoxy,11-undecyleneoxycarbonyl, 10-decylenecarbonyloxy, 12-dodecyleneoxy,12-dodecyleneoxycarbonyl, 11-undecylenecarbonyloxy,3-propyleneiminocarbonyl, 4-butyleneiminocarbonyl,5-pentyleneiminocarbonyl, 6-hexyleneiminocarbonyl,7-heptyleneiminocarbonyl, 8-octyleneiminocarbonyl,9-nonyleneiminocarbonyl, 10-decyleneiminocarbonyl,11-undecyleneiminocarbonyl, 12-dodecyleneiminocarbonyl,2-ethylenecarbonylimino, 3-propylenecarbonylimino,4-butylenecarbonylimino, 5-pentylenecarbonylimino,6-hexylenecarbonylimino, 7-heptylenecarbonylimino,S-octylenecarbonylimino, 9-nonylenecarbonylimino,10-decylenecarbonylimino, 11-undecylenecarbonylimino,6-(3-propyleneiminocarbonyloxy)hexylene, 6-(3-propyleneoxy)hexylene,6-(3-propyleneoxy)hexyloxy, 6-(3-propyleneiminocarbonyloxy)hexyloxy,6-(3-propyleneiminocarbonyl)hexyl, 6-(3-propyleneiminocarbonyl)hexyloxy,1,2-ethylenedioxy, 1,3-propylenedioxy, 1,4-butylenedioxy,1,5-pentylenedioxy, 1,6-hexylenedioxy, 1,7-heptylenedioxy,1,8-octylenedioxy, 1,9-nonylenedioxy, 1,10-decylenedioxy,1,11-undecylenedioxy, 1,12-dodecylenedioxy,2-{[4-(2-oxy-ethyl)cyclohexyl]phenyl}ethoxy,2-[4′-(4-oxybutyl)-1,1′biphenyl-4-yl]ethoxy,2-{4-[4-(2-oxy-ethyl)phenyl}ethoxy,2-{4-[4-(2-carbonyloxyethyl)cyclohexyl]phenyl}-ethoxy,2-[4′-(2-carbonyloxybutyl)-1,1′biphenylene-4-yl]ethoxy,6-{4-[4-(2-carbonyloxyethyl)phenyl}hexyloxy,5-{[4′-(4-oxybutoxy)-1,1′-biphenyl-4-yl]oxy}pentylcarbonyloxy,2-oxyethylene, 3-oxypropylene, 4-oxybutylene, 5-oxypentylene,6-oxyhexylene, 7-oxyheptylene, 8-oxyoctylene, 9-oxynonylene,10-oxydecylene, 11-oxyundecylene, 12-oxydodecylene,2-(oxycarbonyl)ethylene, 3-(oxycarbonyl)propylene,4-(oxycarbonyl)butylene, 5-(oxycarbonyl)pentylene,6-(oxycarbonyl)hexylene, 7-(oxycarbonyl)heptylene,8-(oxycarbonyl)octylene, 9-(oxycarbonyl)nonylene,10-(oxycarbonyl)decylene, 11-(oxycarbonyl)undecylene,12-(oxycarbonyl)dodecylene, 2-(carbonyloxy)ethylene,3-(carbonyloxy)propylene, 4-(carbonyloxy)butylene,5-(carbonyloxy)pentylene, 6-(carbonyloxy)hexylene,7-(carbonyloxy)-heptylene, 8-(carbonyloxy)octylene,9-(carbonyloxy)nonylene, 10-(carbonyloxy)-decylene,11-(carbonyloxy)undecylene, 12-(carbonyloxy)dodecylene,2-(carbonylimino)ethylene, 3-(carbonylimino)propylene,4-(carbonylimino)butylene, 5-(carbonylimino)pentylene,6-(carbonylimino)hexylene, 7-(carbonylimino)heptylene,8-(carbonylimino)octylene, 9-(carbonylimino)nonylene,10-(carbonylimino)decylene, 11-(carbonylimino)undecylene,12-(carbonylimino)dodecylene, 2-iminoethylene, 3-iminopropylene,4-iminobutylene, 5-iminopentylene, 6-iminohexylene, 7-iminoheptylene,8-iminooctylene, 9-iminononylene, 10-iminodecylene, 11-iminoundecylene,12-iminododecylene, 2-iminocarbonylethylene, 3-iminocarbonylpropylene,4-iminocarbonylbutylene, 5-iminocarbonylpentylene,6-iminocarbonylhexylene, 7-iminocarbonylheptylene,8-iminocarbonyloctylene, 9-iminocarbonylnonylene,10-iminocarbonyldecylene, 111-iminocarbonylundecylene,12-iminocarbonyldodecylene, 2-(2-ethyleneoxy)ethylene,2-(3-propyleneoxy)ethylene, 6-(4-butyleneoxy)hexylene,2-(2-ethyleneiminocarbonyl)ethylene,2-(3-propyleneiminocarbonyl)ethylene,6-(4-butyleneiminocarbonyl)hexylene,6-(3-propyleneiminocarbonyloxy)hexylene,6-(3-propyleneiminocarbonyl)hexylene,6-oxyhexyl(2E)-3-[4-(4-oxybutoxy)-3-methoxyphenyl]-2-propenoate,8-oxyoctyl(2E)-3-[4-(5-oxypentoxy)phenyl]-2-propenoate,1,1-bis-[(2E)-3-(4-oxyphenyl)-2-propenoate]undecylene and the like

[0081] It is preferred that the group G is selected from a hydrogenatom; a radically or cationically polymerizable group, or also frommono,- di or -tri-alkoxy or halogeno silanes.

[0082] It is more preferred that G is selected from a hydrogen atom, aradically or cationically polymerizable groups or a monomer unit in ahomo or copolymer from a radical or cationic polymerisation.

[0083] It is especially preferred that G is a radically or cationicallypolymerizable groups as defined above.

[0084] It is also preferred that the group K is a nitrogen atom, acarbon atom, an aromatic, an alicyclic or a CR¹— unit wherein R¹ is asdefined above.

[0085] It is especially preferred that the group K is selected form1,2,3-benzenetriyl, 1,3,4-benzenetriyl, 1,3,5-benzenetriyl or a groupCR¹—.

[0086] It is also preferred that the group J is a carbon atom, anaromatic or an alicyclic unit.

[0087] It is especially preferred that the group J is a carbon atom.

[0088] Preferred core portions are groups of formulae IIIa, IIIb, IIIc,IIId.

[0089] More preferred core portions are groups of formulae IIIa andIIIb.

[0090] Dendrimers used in the present invention may be prepared inaccordance with known methods, such as those described in Advances inpolymer science, Vol. 142 (1999).

[0091] Additives such as silane-containing compounds andepoxy-containing crosslinking agents may be added to the dendrimers ofthe invention in order to improve the adhesion of the dendrimer to asubstrate. Suitable silane-containing compounds are described in Plast.Eng., Vol. 36 (1996) (Polyimides, fundamentals and applications).Suitable epoxy-containing crosslinking agents include4,4′-methylenebis-(N,N-diglycidylaniline), trimethylolpropanetriglycidyl ether, benzene-1,2,4,5-tetra-carboxylic acid1,2:4,5-N,N′-diglycidyldiimide, polyethylene glycol diglycidyl ether,N,N-diglycidylcyclohexylamine and the like.

[0092] Further additives such as a photosensitiser, a photoradicalgenerator and/or a cationic photoinitiator may also be added to thedendrimers of the invention. Suitable photo-active additives include2,2-dimethoxyphenylethanone, a mixture of diphenylmethanone andN,N-dimethylbenzenamine or ethyl 4-(dimethylamino)benzoate, xanthone,thioxanthone, IRGACURE™ 184, 369, 500, 651 and 907 (Ciba), Michler'sketone, triaryl sulfonium salts and the like.

[0093] The dendrimers according to the invention are used as orientationlayers for the liquid crystals and in the construction of unstructuredand structured optical elements and multi-layer systems. They may beused alone or in combination with polymers, oligomers, monomers,photoactive polymers, photoactive oligomers and/or photoactive monomers,depending upon the application to which the polymer layer is to be put.It will therefore be appreciated that by varying the composition of thepolymer layer it is possible to control properties such as an inducedpretilt angle, good surface wetting, high voltage holding ratio, aspecific anchoring energy etc. One or more of the orientation layers ofthe present invention may be used in the construction of electroopticalcomponents.

[0094] Suitable photoactive polymers or oligomers for combination withthe dendrimers of the invention are described for example inEP-A-0611786, WO-A-96/10049, EP-A-0763552, U.S. Pat. No. 5,965,761,EP-A-0857728, EP-A-0860455 and WO-A-99/15576.

[0095] Suitable photoactive monomers are for example those described inU.S. Pat. No. 5,567,349, U.S. Pat. No. 5,650,534, U.S. Pat. No.5,593,617, U.S. Pat. No. 5,851,427, U.S. Pat. No. 5,707,544, U.S. Pat.No. 5,851,424, U.S. Pat. No. 5,700,393, U.S. Pat. No. 5,800,733,WO-98/52905, WO-00/05189, WO-00/48985 and WO-00/55110.

[0096] The following non-limiting examples further describe the presentinvention. Variations on these falling within the scope of the inventionwill be apparent to a person skilled in the art.

EXAMPLES Synthetic Example 1

[0097] Preparation of 1,6-hexandioldi[3,5-bis[(8-{2-methoxy-4-[(1E)-3-methoxy-3-oxo-1-propenyl]phenoxy}octyl)oxy]benzyloxy]benzoate

[0098] 0.390 g (1.0 mmol) of 1,6-hexandiol di(3,5-dihydroxy)benzoate,1.1 g (4.2 mmol) triphenylphosphine were dissolved in 5.4 mltetrahydrofurane, 3.1 g (4.0 mmol)3,5-bis[(8-{2-methoxy-4-[(1E)-3-methoxy-3-oxo-11-propenyl]phenoxy}octyl)oxy]benzylalcohol and 10 ml tetrahydrofurane were added. 1.83 g (4.2 mmol) of a40% solution of azodicarboxylic acid diethyl ester in toluene was addeddropwise thereto over a period of 35 minutes. The mixture wassubsequently allowed to react for 3.5 hours at 25° C. The reactionmixture was then partitioned between ethyl acetate and water. Theorganic phase was washed repeatedly with water, dried over sodiumsulfate, filtered and concentrated by rotary evaporation. Firstchromatography of the residue on 240 g silica gel using toluene:ethylacetate (9:1) as eluant and second chromatography on 100 g LiChroprepRP-18 using acetonitrile:tetrahydrofurane (85:15) as eluant yielded 1.58g (46.0%) of 1,6-hexandioldi[3,5-bis[(8-{2-methoxy-4[(1E)-3-methoxy-3-oxo-1-propenyl]phenoxy}octyl)oxy]benzyloxy]benzoate(“Dendrimer I”). Tg=41.2° C.

[0099] The intermediates used as starting material were prepared inaccordance with the following procedure.

[0100] Preparation ofmethyl(2E)-3-{4-[(8-chloroctyl)oxy]-3-methoxyphenyl}-2-propenoate

[0101] 20.0 g (96.06 mmol)methyl(2E)-3-(4-hydroxy-3-methoxyphenyl)-2-propenoate, 16.6 g (100.9mmol) 8-chlor-1-octanol and 27.7 g (105.7 mmol) of triphenylphosphinewere dissolved in 400 ml of tetrahydrofurane. The colourless solutionwas subsequently cooled to 0° C. and 46.0 g (105.7 mmol) of a 40%solution of azodicarboxylic acid diethyl ester in toluene was addeddropwise thereto over a period of 25 minutes. The mixture wassubsequently allowed to react for 4 hours at 0° C. The reaction mixturereduced in volume by evaporation. The resulting residue was added to amixture of methanol and water (3:2) and was then extracted with amixture of tert.-butyl-methylether:hexane 1:1. Thetert.-butyl-methylether:hexane phase was washed repeatedly with water,dried over magnesium sulfate, filtered and concentrated by rotaryevaporation. The crude product was recrystallised from 2-propanolyielded 30.8 g (90%)methyl(2E)-3-{4-[(8-chloroctyl)oxy]-3-methoxyphenyl}-2-propenoate aswhite crystals.

[0102] Preparation ofmethyl(2E)-3-{4-[(8-iodoctyl)oxy]-3-methoxyphenyl}-2-propenoate

[0103] 26.8 g (75.52 mmol)methyl(2E)-3-{4-[(S-chloroctyl)oxy]-3-methoxyphenyl}-2-propenoate wasdissolved in 1000 ml acetone. 65.16 g (435.15 mmol) sodium iodide wereadded. The reaction suspension was heated at reflux temperature for 24hours. The reaction mixture was partitioned between diethylether andwater. The organic phase was washed repeatedly with water, dried oversodium sulfate, filtered and concentrated by rotary evaporation. Thecrude product was recrystallised from 2-propanol yielded 30.1 g (90%)methyl(2E)-3-{4-[(S-iodoctyl)oxy]-3-methoxyphenyl}-2-propenoate as whitecrystals.

[0104] Preparation of3,5-bis[(8-{2-methoxy-4[(1E)-3-methoxy-3-oxo-1-propenyl]phenoxy}octyl)oxy]benzylalcohol

[0105] 5.87 g (13.15 mmol)methyl(2E)-3-{4-[(8-iodoctyl)oxy]-3-methoxyphenyl]-2-propenoate, 0.872 g(6.26 mmol) 3,5-dihydroxybenzyl alcohol were dissolved in 50 mlN,N-dimethylformamide. 4.33 g (31.31 mmol) potassium carbonate wereadded. The reaction suspension was then heated at reflux temperature for24 hours. The reaction mixture was partitioned between ethyl acetate anda saturated sodium chloride solution. The organic phase was washedrepeatedly with water, dried over sodium sulfate, filtered andconcentrated by rotary evaporation. Chromatography of the residue on 240g silica gel using first toluene: ethyl acetate (4:1)then (7:3) yielded2.15 g (42%)3,5-bis[(8-{2-methoxy-4-[(1E)-3-methoxy-3-oxo-1-propenyl]phenoxy}octyl)oxy]benzylalcohol as colorless oil.

[0106] Preparation of 1,6-hexandiol bis-(3.5 dihydroxy)benzoate

[0107] 4.85 g (31.5 mmol) 3,5-dinitrobenzoic acid was suspended in 31 mlAcetonitrile. 4.80 g (31.5 mmol)1,8-diazabicyclo[5.4.0]undec-7-ene(1,5-5) (DBU) were added dropwise overa period of 10 minutes. 3.66 g (15.0 mmol) 1,6-dibromohexane were addedand the resulting mixture was then heated to 84° C. for 18 hours. Thereaction mixture was cooled and then partitioned between diethyletherand water. The organic phase was washed repeatedly with water, driedover sodium sulfate, filtered and concentrated by rotary evaporation.Chromatography of the residue on 240 g silica gel using firsttoluene:ethyl acetate (4:1) then (1:1) as eluant yielded 3.39 g (53%) of1,6-hexandiol bis-(3,5 dihydroxy)benzoate as beige crystals.

Synthetic Example 2

[0108] Preparation of 1,8-octandiolbis-[3,5-bis({-2,2-bis[({4-[(1E)-3-methoxy-3-oxo-1-propenyl]benzoyl}oxy)methyl]propanoyl}amino)]benzoate

[0109] 0.86 g (0.978 mmol) 1,8-octandiolbis(3,5-bis{[2,2,-bis(hydroxymethyl)propanoyl]amino}benzoate, 1.815 g(8.80 mmol) 4-[(1E)-3-methoxy-3-oxo-1-propenyl]benzoic acid, 0.29 g(0.978 mmol) 4-(dimethylamino)-pyridinium p-toluenesulfonate in 30 mldichloromethane and 10 ml tetrahydrofurane was cooled to 0° C. and 1.73g (8.37 mmol) N,N′-dicyclohexylcarbodiimide were added. The mixture wassubsequently allowed to react for 48 hours at 25° C. and filtered. Thefiltrate was concentrated by evaporation. The crude product was firstpurified by chromatography on 150 g silica gel using toluene:ethylacetate (7:3) as eluant then was reprecipitated form THF (20 ml) into400 ml methanol to yield 1.86 g (80%) 1,8-octandiolbis-[3,5-bis({-2,2-bis[({4-[(1E)-3-methoxy-3-oxo-1-propenyl]benzoyl}oxy)methyl]propanoyl}amino)]benzoate(“Dendrimer 2”) as white powder. Tg=83° C.

[0110] The intermediates used as starting material were prepared inaccordance with the following procedure.

[0111] Preparation of 1,8-octandiol bis(3,5 diamino)benzoate

[0112] 3.57 g (6.68 mmol) 1,8-octandiol bis-(3,5 dinitro)benzoate weredissolved in a mixture of 150 ml N,N-dimethylformamide and 17 ml water.21.66 g (80.14 mmol) ferric chloride hexahydrate and 8.73 g (133.56mmol) zinc powder were added, the temperature rise to 45° C. The mixturewas allowed to react for 2 hours. The reaction mixture was thenpartitioned between ethyl acetate and water and filtered. The organicphase was washed repeatedly with water, dried over sodium sulfate,filtered and concentrated by rotary evaporation. The crude product wasfirst recrystallised from a ethyl acetate:hexane 2:1 mixture and secondform ethanol yielded 2.04 g (73%) of 1,8-octandiol bis(3,5diamino)benzoate as beige crystals.

[0113] Preparation of 1,8-octandiolbis(3,5-bis{[(2,2,5-trimethyl-1,3-dioxan-5-yl)carbonyl}amino)benzoate

[0114] A mixture of 0.946 g (5.43 mmol)2,2,5-trimethyl-1,3-dioxane-5-carboxylic acid, 0.500 g (1.21 mmol)1,8-octandiol bis(3,5 diamino)benzoate, 0.14 g (0.48 mmol)4-(dimethylamino)pyridinium p-toluenesulfonate in 20 ml dichloromethanewas cooled to 0° C. and 1.24 g (6.03 mmol) N,N′-dicyclohexylcarbodiimidewere added. The mixture was subsequently allowed to react for 72 hoursat 25° C. and filtered. The filtrate was concentrated by evaporation.Chromatography of the residue on 150 g silica gel using tert.butyl-methyl ether:ethyl acetate 3:1 as eluant yielded 1.10 g (87%)1,8-octandiol bis(3,5-bis{[(2,2,5-trimethyl-1,3-dioxan-5-yl)carbonyl}amino)benzoate as whitecrystals.

[0115] Preparation of 1,8-octandiolbis(3,5-bis{[2,2,-bis(hydroxymethyl)propanoyl]amino}benzoate

[0116] 1.10 g (1.06 mmol) 1,8-octandiolbis(3,5-bis{{(2,2,5-trimethyl-1,3-dioxa-5-yl)carbonyl}amino)benzoate wasdissolved in 10 ml methanol and 10 ml tetrahydrofurane. 0.50 g of Dowex50Wx2 resin and the reaction mixture was stirred for 4 hours at roomtemperature. The Dowex resin was filtered off and washed withtetrahydrofurane. The filtrate was concentrated by rotary evaporationyielded 0.86 g (92%) 1,8-octandiolbis(3,5-bis{[2,2,-bis(hydroxymethyl)propanoyl]amino}benzoate asyellowish crystals.

Synthetic Example 3

[0117] Preparation of6-{[3,5-bis({3,5-bis[(8-42-methoxy-4-[(1E)-3-methoxy-3-oxo-1-propenyl]phenoxy}octyl)oxy]benzyl}oxy)benzoyl]oxy}hexylmethacrylate.

[0118] 1.10 g (1.31 mmol)3,5-bis[(8-{2-methoxy-4-[(1E)-3-methoxy-3-oxo-1-propenyl]phenoxy}octyl)oxy]benzylbromide, 0.204 g (0.63 mmol) 6-(methacryloyloxy)hexyl3,5-dihydroxybenzoate, 17 mg (0.06 mmol) 18-Crown-6 were dissolved in 20ml 2-butanone. 0.114 g (0.82 mmol) potassium carbonate were added. Thereaction suspension was then heated at reflux temperature for 24 hours.The reaction mixture was partitioned between ethyl acetate and water.The organic phase was washed repeatedly with water, dried over sodiumsulfate, filtered and concentrated by rotary evaporation. Chromatographyof the residue on 10 g LiChroprep RP-18 using first Acetonitrile thentetrahydrofurane) as eluant yielded 0.90 g (77%)6-{[3,5-bis({3,5-bis[(8-{2-methoxy-4-[(1E)-3-methoxy-3-oxo-1-propenyl]phenoxy}octyl)oxy]benzyl}oxy)benzoyl]oxy}hexylmethacrylate (“Dendrimer 3”) as colorless oil.

[0119] The intermediates used as starting material were prepared inaccordance with the following procedure.

[0120] Preparation of3,5-bis[(8-{2-methoxy-4-[(1E)-3-methoxy-3-oxo-1-propenyl]phenoxy}octyl)oxy]benzylbromide

[0121] 2.39 g (3.08 mmol) of3,5-bis[(8-{2-methoxy-4-[(1E)-3-methoxy-3-oxo-1-propenyl]phenoxy}octyl)oxy]benzylalcohol, 1.14 g (3.42 mmol) tetrabromomethane were dissolved in 25 mldichloromethane. The solution was subsequently cooled to 0° C. and asolution of 0.86 g (3.29 mmol) triphenylphosphine in 20 mldichloromethane was added dropwise thereto over a period of 1 hour. Themixture was subsequently allowed to react for 20 h at 25° C. and reducedin volume by evaporation. Chromatography of the residue on 120 g silicagel using first toluene:ethyl acetate (19:1) then (4:1) as eluantyielded 1.94 g (78%)3,5-bis[(8-{2-methoxy-4-[(1E)-3-methoxy-3-oxo-1-propenyl]phenoxy}octyl)oxy]benzylbromide as colorless oil.

[0122] Preparation of 6-(methacryloyloxy)hexyl 3,5-dihydroxybenzoate

[0123] 2.27 g (14.72 mmol) 3,5-dihydroxybenzoic acid was dissolved in 32ml N,N-dimethylformamide. A solution of 2.24 g (14.72 mmol)1,8-diazabicyclo[5.4.0]undec-7-ene(1,5-5) (DBU) and 17 mlN,N-dimethylformamide were added dropwise over a period of 30 minutes. Asolution of 3.96 g (13.38 mmol) 6-iodohexyl 2-methacrylate and 17 mlN,N-dimethylformamide were added dropwise over a period of 40 minutesand the resulting mixture was then allowed to react for 22 hours at 25°C. The reaction mixture was cooled and then partitioned between ethylacetate and water. The organic phase was washed repeatedly with water,dried over sodium sulfate, filtered and concentrated by rotaryevaporation. Chromatography of the residue on 110 g silica gel usingfirst toluene:ethyl acetate (4:1) then (7:3) as eluant yielded 3.57 g(80%) 6-(methacryloyloxy)hexyl 3,5-dihydroxybenzoate as white powder.

Synthetic Example 4

[0124] Polymerization of Dendrimer 3

[0125] A mixture of 0.398 g (0.216 mmol) Dendrimer 3 and 0.4 mg (0.0024mmol) α.α′-azoisobutyronitrile (AIBN) in 0.50 ml dry tetrahydrofuran(THF) was degassed in a sealable tube. The tube was then sealed underargon and stirred at 60° C. for 16.5 h. The resulting polymerprecipitated into 50 ml t.butyl-methyl ether and collected. The polymerwas reprecipitated from THF (2.0 ml) into 30 ml methanol to yield 0.12 g(30%)]Poly-[1-[6-{[3,5-bis({3,5-bis[(8-{2-methoxy-4-[(1E)-3-methoxy-3-oxo1-propenyl]phenoxy}octyl)oxy]benzyl}oxy)benzoyl]oxy}hexyloxy]-1-methylethylene]as a solid; M_(n)=4.2×10⁴, pdi=1.48.

Synthetic Example 5

[0126] Preparation ofdi[3,5-bis({4-[3,5-bis[({6-[(2-oxo-2H-chromen-7-yl)oxy]hexyl}oxy)carbonyl]phenoxy]butoxy}carbonyl)phenyl]1,1-biphenyl-4,4′-dicarboxylate

[0127] 0.28 g (1.0 mmol) 4,4′-Biphenyldicarbonyl chloride, 4.00 g (2.5mmol)1,3-bis(4-{3,5-bis[({6-[(2-oxo-2H-chromen-7-yl)oxy]hexyl}oxy)carbonyl]phenoxy}butyl)5-hydroxyisophthalate and 6 mg (0.05 mmol) 4-dimethylaminopyridine wereadded in 50 ml toluene. Thereafter 5.0 ml pyridine were added and thereaction mixture was allowed to react for 18 hours at refluxingtemperature. The reaction mixture was partitioned between ethyl acetateand water. The organic phase was washed repeatedly with water, driedover sodium sulfate, filtered and concentrated by rotary evaporation.First chromatography of the residue on silica gel and secondchromatography on LiChroprep RP-18 yieldeddi[3,5-bis({4-[3,5-bis[({6-[(2-oxo-2H-chromen-7-yl)oxy]hexyl}oxy)carbonyl]phenoxy]butoxy}carbonyl)phenyl]1,1-biphenyl-4,4′-dicarboxylate.

[0128] The intermediates used as starting material were prepared inaccordance with the following procedure.

[0129] Preparation of 7-(6-chlorohexyl)coumarin

[0130] Preparation can be carried out analogously to Synthetic Example 1using 16.2 g (100 mmol) 7-Hydroxycoumarin, 14.3 g (105 mmol)6-chlorohexanol, 28.8 g (110 mmol) triphenylphosphine and 47.9 g (110mmol) of a 40% solution of azodicarboxylic acid diethyl ester in tolueneto yielded 7-(6-chlorohexyl) coumarin.

[0131] Preparation ofbis[6-[(2-oxo-2H-chromen-7-yl)oxy]hexyl}5-hydroxyisophthalate

[0132] 5.64 g (20.0 mmol) 7-(6-chlorohexyl) coumarin and 1.82 g (10.0mmol) 5-hydroxyisophthalic acid were dissolved in 240 ml1-methyl-2-pyrrolidon. 4.87 g (58.0 mmol) sodium hydrogencarbonate wereadded. The reaction suspension was then heated at 80° C. for 4 hours.The reaction mixture was partitioned between ethyl acetate and water.The organic phase was water, dried over sodium sulfate, filtered andconcentrated by rotary evaporation. Chromatography of the residueyielded bis {6-[(2-oxo-2H-chromen-7-yl)oxy]hexyl}5-hydroxyisophthalate.

[0133] Preparation ofbis{6-[(2-oxo-2H-chromen-7-yl)oxy]hexyl}5-(4-chlorobutoxy)isophthalate

[0134] Preparation can be carried out analogously to Synthetic Example 1using 6.71 g (10.0 mmol) bis{6-[(2-oxo-2H-chromen-7-yl)oxy]hexyl}5-hydroxyisophthalate, 1.14 g (10.5mmol) 4-chloro-1-butanol, 2.88 g (11.0 mmol) triphenylphosphine and 4.79g (11.0 mmol) of a 40% solution of azodicarboxylic acid diethyl ester intoluene to yieldbis{6-[(2-oxo-2H-chromen-7-yl)oxy]hexyl}5-(4-chlorobutoxy)isophthalate.

[0135] Preparation of1,3-bis(4-13,5-bis[({6-[(2-oxo-2H-chromen-7-yl)oxy]hexyl 1,oxy)carbonyl]phenoxy}butyl)5-hydroxyisophthalate

[0136] Preparation can be carried out as above using 15.2 g (20.0 mmol)bis {6-[(2-oxo-2H-chromen-7-yl)oxy]hexyl}5-(4-chlorobutoxy)isophthalate,1.82 g (10.0 mmol) 5-hydroxyisophthalsäure and 4.87 g (58.0 mmol) sodiumhydrogencarbonate to yield 1,3-bis(4{3,5-bis[({6-[(2-oxo-2H-chromen-7-yl)oxy]hexyl}oxy)carbonyl]phenoxy}butyl)5-hydroxyisophthalate.

Synthetic Example 6

[0137] Preparation of1,1,1-tris[4-{([2,2-bis{([2,2-bis{[(6-{4-[(1E)-3-oxo-1-butenyl]phenoxy}hexanoyl)oxy]methyl}propanoyl]oxy)methyl}propanoyl]oxy)phenyl}]ethane

[0138] 1.00 g (3.39 mmol) 6-{(4-[(1E)-3-oxo-1-butenyl]phenoxy}hexanoylchloride were diluted in a small amount of tetrahydofurane and added at0° C. dropwise to a solution of 0.35 g (0.26 mmol)1,1,1-tris[4-{([2,2-bis{([2,2-bis{hydroxymethyl}propanoyl]oxy)methyl}propanoyl]oxy)phenyl}]ethane,0.180 g (1.47 mmol) 4-dimethylaminopyridine, 0.446 g (4.41 mmol)triethylamine and 20 ml tetrahydrofurane. After stirring at 0° C. for 1hour, the mixture was allowed to react at 25° C. for a further 24 hours.The mixture was concentrated by rotary evaporation. The residue wasdissolved in dichloromethane washed repeatedly first with a saturatedsodium hydrogencarbonte solution and then with 2N HCl. The organic phasewas dried over sodium sulfate, filtered and concentrated by rotaryevaporation. The dendrimer was reprecipitated from tetrahydrofurane intomethanol to yield 1,1,1-tris[4{([2,2-bis{([2,2-bis{[(6-{4-[(1E)-3-oxo-1-butenyl]phenoxy}hexanoyl)oxy]methyl}propanoyl]oxy)methyl}propanoyl]oxy)phenyl}]ethane.

[0139] The intermediates used as starting material were prepared inaccordance with the procedure described by Frechet, J. M. inMacromolecules 1998, 31, 4061, and with the following procedure.

[0140] Preparation of 6-{4-[(1E)-3-ooxobut-1-enyl]phenoxy}hexanoic acid

[0141] 1.62 g (10.0 mmol) 4-Hydroxybenzylideneacetone, 3.98 g (15.0mmol) tetrahydro-2H-pyran-2-yl 5-bromopentanoate were dissolved inN,N-dimethylformamide. 3.45 g (25.0 mmol) potassium carbonate wereadded. The reaction suspension was then heated at 70° C. for 8 hours.The reaction mixture was partitioned between ethyl acetate and asaturated sodium chloride solution. The organic phase was washedrepeatedly with water, dried over sodium sulfate, filtered andconcentrated by rotary evaporation. The residue was dissolved in 50 mltetrahydrofurane and 1 ml HCl concentrated was added. The mixture wasstirred at 25° C. for 45 min, partitioned between dichloromethane and asaturated sodium chloride solution. The organic phase was washedrepeatedly with water, dried over sodium sulfate, filtered andconcentrated by rotary evaporation to yield6-{4-[(1E)-3-ooxobut-1-enyl]phenoxy}hexanoic acid.

Example 1

[0142] Preparation of Alignment Layers Using Dendrimer 3

[0143] a/ Preparation of Alignment Layers

[0144] A 1% wt solution of the photoreactive Dendrimer 3, including ornot a 2% wt of a photoinitiator (Irgacure 184 from Ciba), incyclopentanone was spin coated at 3000 rpm onto glass plates. The layerswere annealed at temperature above 70° C. to remove residual solvent andtreated using various cross-linking conditions:

[0145] Treatment 1: The layers were irradiated with isotropic UV lightto cross-link the polymerisable groups, then exposed to linearlypolarized UV light with an energy up to 660 mJ/cm², from a 350 W mercuryhigh pressure lamp.

[0146] Treatment 2: The layers were exposed to linearly polarized UVlight, as indicated above, then irradiated with isotropic UV light tocross-link the polymerisable groups.

[0147] Treatment 3: The layers are exposed to linearly polarizedUV-light and simultaneously cross-linked under N₂ atmosphere.

[0148] b/ Preparation of a Retardation Layer

[0149] The resulting layers were then spin coated with an LCP mixtureCB483 (available from Vantico AG), annealed at 50° C. for 5 minutes andthen cross-linked with isotropic UV light for 5 minutes. The total LCPfilm thickness is about 1 micrometer. Observation of the coatingsbetween crossed polarizers showed that the liquid crystal is uniformlyoriented for exposure energies above 66 mJ/cm². Using a tilt compensatorand a polarization microscope, the orientation direction of LCPmolecules was established to be parallel to the direction ofpolarization of UV light which had irradiated the alignment layers.Contrast ratio as high as 1000:1 was measured.

[0150] c/ Preparation of an LC Cell

[0151] With the coated sides facing inwards, coated plates from Example1a were assembled into parallel-sided LC cells using glass spheres of 20micrometers thickness as spacer. Two different cells, cell1 and cell2,were prepared using alignment layers according to treatment 1 andtreatment 2, respectively. The cells were filled with a nematic liquidcrystal mixture MLC12000-000 (Merck) at a temperature well above it'snematic-isotropic transition temperature (T_(c)=89° C.), and slowlycooled to room temperature. Observation of the prepared cell betweencrossed polarizers showed that the liquid crystal is uniformly oriented.Using a tilting compensator and a polarization microscope, theorientation direction of the LC molecules was established to be parallelto the direction of polarization of UV light which had irradiated thealignment layers.

[0152] For both cells the tilt angle generated in the LC layer, measuredusing the standard crystal rotation method (TBA105 from AutronicsMelchers), was 0.2°. It was also found that illumination times requiredto align the LC mixture are smaller using the treatment 1 of Example 1a.

Example 2

[0153] Preparation of Alignment Layers Using Mixtures of Dendrimer 3 anda Photoactive Monomer

[0154] Solution Sol 1: A binary mixture of 90% of photoreactiveDendrimer 3 and 10% of a photoactive monomer of the type disclosed inWO-00/55110 and including 2 parts of a photoinitiator (Irgacure 184 fromCiba) was added to cyclopentanone to achieve a 2% wt solution. Thesolution was then stirred at room temperature for 10 minutes andfiltered over a 0.2 micrometer Teflon filter.

[0155] Solution Sol2: A binary mixture of 70% of photoreactive Dendrimer3 and 30% of the photoactive monomer used for Sol1 and including 2 partsof a photoinitiator (Irgacure 184 from Ciba), was added tocyclopentanone to achieve a 2% wt solution. The solution was thenstirred at room temperature for 10 minutes filtered over a 0.2micrometer Teflon filter.

[0156] Each of these solutions was spin coated at 3000 rpm onto twoITO-coated glass plates. The resulting films were cross-linked andlinearly polarized according to treatment 1 of Example 1a. Then thelayers were assembled to fabricate LC cells as indicated in Example 1c.Observation of the prepared cells between crossed polarizers showed thatthe liquid crystal is uniformly oriented. Using a tilting compensatorand a polarization microscope, the orientation direction of the LCmolecules was established to be parallel to the direction ofpolarization of UV light which had irradiated the alignment layers. Themeasured tilt angle generated in the LC layer using a 66 mJ/cm2 exposureenergy was about 1° for alignment layers made from the solution Sol1 andabout 90° using alignment layers made from Sol2.

Example 3

[0157] Preparation of Alignment Layers UsingPoly-[1-[6-{[3,5-bis({3,5-bis[(8-{2-methoxy-4-[(1E)-3-methoxy-3-oxo-1-propenyl]phenoxy}octyl)oxy]benzyl}oxy)benzoyl]oxy}-hexyloxy]-1-methylethylene]

[0158] A 2% solution ofPoly-[1-[6-{[3,5-bis({3,5-bis[(8-{2-methoxy-4-[(1E)-3-methoxy-3-oxo-1-propenyl]phenoxy}octyl)oxy]benzyl}oxy)benzoyl]oxy}hexyloxy]-1-methylethylene](Synthetic Example 4) in cyclopentanone was spin coated at 3000 rpm ontoITO-coated glass substrates and annealed for 10 minutes at 180° C. Thelayers were exposed to linearly polarized UV light from a 350 W mercuryhigh pressure lamp. The resulting aligning layers were assembled tofabricate LC cells as described in Example 1c. Observation of theprepared cell between crossed polarizers showed that the liquid crystalis uniformly oriented. Using a tilting compensator and a polarizationmicroscope, the orientation direction of the LC molecules wasestablished to be parallel to the direction of polarization of WV lightwhich had irradiated the alignment layers. Tilt angles are generated inthe LC layer, which were measured using the standard crystal rotationmethod (TBA105 from Autronics Melchers) as of about 36° using anexposure energy of 33 mJ/cm² and about 190 using an exposure energy of66 mJ/cm².

Example 4

[0159] Preparation of Alignment Layers Using Dendrimer 1

[0160] A 2% solution of the photoreactive Dendrimer 1 in cyclopentanonewas spin coated at 3000 rpm onto glass substrates and annealed attemperature above 70° C. to remove residual solvent. The layers wereexposed to linearly polarized UV light, with energies up to 660 mJ/cm²,from a 350 W mercury high pressure lamp. The intensity of the U light atthe plate was determined as 1 mw/cm².

[0161] Then two layers were assembled to fabricate an LC cell asindicated in Example 1c. Observation of the prepared cell betweencrossed polarizers showed that the liquid crystal is uniformly oriented.Using a tilting compensator and a polarization microscope, theorientation direction of the LC molecules was established to be parallelto the direction of polarization of UV light which had irradiated thealignment layers. The tilt angle generated in the LC layer, measuredusing the standard crystal rotation method (TBA105 from AutronicsMelchers), is about 0.20.

Example 5

[0162] Preparation of Alignment Layers Using Mixtures of a Dendrimer anda Photoreactive Polyimide

[0163] A 2% wt solution was fabricated using a binary mixture consistingof 95 parts of a photoreactive polyimide (resulting form thepolycondensation reaction between 1,2,3,4-cyclobutanetetracarboxylicacid dianhydride and 6-{2-methoxy-4-[(1E)-3-oxo-1-propenyl]phenoxy}hexyl3,5-diaminobenzoate) of the type disclosed in WO-A-99/15576 and 5 partsof Dendrimer 3. The solution was then stirred at room temperature for 10min. and filtered over a 0.2 micrometer Teflon filter. The solution wasspin coated at 3000 rpm onto ITO-coated glass plates. The resultingfilms were then predried for 15 minutes at 130° C. and then imidised for1 hour at 180° C. to, form the polyimide. The plates were thenirradiated for 90 seconds with linearly polarized UV light of a 350 Whigh-pressure mercury vapor lamp. A liquid crystalline mixture ofdiacrylates (AN43 from Rolic Research Ltd) was spin-coated, annealed at50° C. during 5 minutes and finally cross-linked with isotropic UV lightfor 5 minutes. The total LCP film thickness was about 1 micrometer.Observation of the coatings between crossed polarizers showed that theliquid crystal is uniformly oriented. Using a tilt compensator and apolarization microscope, the orientation direction of the LCP moleculeswas established to be parallel to the direction of polarization of UVlight which had irradiated the alignment layers. Contrast ratio as highas 1300:1 was measured. By repeating the same experiment using a 2 wt %solution of pure photoreactive polyimide, instead of the above mixture,contrast ratio of only 200:1 was measured.

1. Photoreactive dendrimers comprising a core portion, branching unitsand terminal groups, wherein at least one terminal group and/orbranching unit is a photoreactive group.
 2. Photoreactive dendrimersaccording to claim 1, wherein the photoreactive groups are able toundergo photocyclization, in particular [2+2]-photocyclization. 3.Photoreactive dendrimers according to claim 1, wherein the photoreactivegroups are sensitive to UV or laser light, in particular linearlypolarized UV light.
 4. Photoreactive dendrimers according to claim 1,wherein the photoreactive groups are cinnamates, coumarins,benzylidenephthalimidines, benzylideneacetophenones, diphenylacetylenesstilbazoles, uracyl, quinolinone, maleinimides, or cinnamylidene aceticacid derivatives.
 5. Photoreactive dendrimers according to claim 4,wherein the photoreactive groups are cinnamates, coumarins,benzylideneacetophenones, or maleinimides.
 6. Photoreactive dendrimersaccording to claim 4, wherein the photoreactive groups are cinnamates orcoumarins.
 7. Photoreactive dendrimers according to claim 1, wherein thephotoreactive groups are represented by the general formulae Ia and Ib:

wherein the broken line indicates the point of linkage to the outermostgeneration of the dendrimer and A represents pyrimidine-2,5-diyl,pyridine-2,5-diyl, 2,5-thiophenylene, 2,5-furanylene, 1,4- or2,6-naphthylene; or phenylene, which is unsubstituted or mono- orpoly-substituted by fluorine, chlorine or by a cyclic, straight-chain orbranched alkyl residue which is unsubstituted mono- or poly-substitutedby fluorine, chlorine, having 1 to 18 carbon atoms, wherein one or morenon-adjacent —CH₂— groups may independently be replaced by a group C;wherein C represents a group selected from —O—, —CO—, —CO—O—, —O—CO—,—NR¹—, —NR¹—CO—, —CO—NR¹—, —NR¹—CO—O—, —O—CO—NR¹—, —NR¹—CO—NR¹—,—CH═CH—, —C═C—, —O—CO—O— and —Si(CH₃)₂—O—Si(CH₃)₂—, wherein R¹represents hydrogen or lower alkyl; B represents hydrogen, or a groupwhich is able to react or interact with a second material like polymers,oligomers, monomers, photoactive polymers, photoactive oligomers and/orphotoactive monomers or surfaces; S₁ and S₂ each independently of theother represent a single bond or a spacer unit such as a straight-chainor branched alkylene group which is unsubstituted, mono orpoly-substituted by fluorine, chlorine, having 1 to 40 carbon atoms,wherein one or more non-adjacent —CH₂— groups may independently bereplaced by a group D, with the proviso that oxygen atoms are notdirectly attached to each other; wherein D represents a group selectedfrom —O—, —CO—, —CO—O—, —O—CO—, —NR¹—, —NR¹—CO—, —CO—NR¹—, —NR¹—CO—O—,—O—CO—NR¹—, —NR¹—CO—NR¹—, —CH═CH—, —C≡C—, —O—CO—O— and—Si(CH₃)₂—O—Si(CH₃)₂—, an aromatic or an alicyclic group, wherein R¹represents hydrogen or lower alkyl; Q represents oxygen or —NR¹— whereinR¹ represents hydrogen or lower alkyl; and X, Y each independently ofthe other represents hydrogen, fluorine, chlorine, cyano, alkyloptionally substituted by fluorine having 1 to 12 carbon atoms in whichoptionally one or more non-adjacent alkyl —CH₂— groups are replaced by—O—, —CO—O—, —O—CO— and/or —CH═CH—.
 8. Photoreactive dendrimersaccording to claim 7, wherein A is selected from pyrimidine-2,5-diyl,pyridine-2,5-diyl, 2,5-thiophenylene, 2,5-furanylene, 1,4- or2,6-naphthylene and phenylene, which is unsubstituted or substituted bya cyclic, straight-chain or branched alkyl residue which isunsubstituted, mono- or poly-substituted by fluorine, chlorine havingfrom 1 to 12 carbon atoms in which optionally one or more non-adjacentalkyl —CH₂— groups are replaced by —O—, —CO—, —CO—O—, —O—CO—, —CH═CH—and C—C≡C—.
 9. Photoreactive dendrimers according to claim 8, wherein Ais selected from 2,5-furanylene, 1,4- or 2,6-naphthylene and phenylene,which is unsubstituted or substituted by a cyclic, straight-chain orbranched alkyl residue having 1 to 12 carbon atoms in which optionallyone or more non-adjacent alkyl —CH₂— groups are replaced by —O—, —CO—,—CO—O—, —O—CO—, —CH═CH— and —C≡C—.
 10. Photoreactive dendrimersaccording to 7, wherein B is a radically or cationically polymerizablegroup; hydrophilic anionic groups like groups consisting of —OSO₂O⁻,—SO₂O⁻, —CO₂ ⁻, (—O)₂P(O)O⁻, —P(O)(O⁻)₂, —OP(O)(O⁻)₂, —P(O⁻)₂ and—OP(O⁻)₂ in protonated or salt form e.g. as alkali metals salts orammonium salts; polar groups like alcohol, thiol and isocyanate; andalso mono-di-tri-alkoxy or halogeno silanes.
 11. Photoreactivedendrimers according to claim 10, wherein B is selected from hydrogen,radically or cationically polymerizable groups or mono-, di-, tri-alkoxyor halogeno silanes.
 12. Photoreactive dendrimers according to claim 10,wherein B is selected from hydrogen or radically or cationicallypolymerizable groups.
 13. Photoreactive dendrimers according to claim10, wherein B is hydrogen.
 14. Photoreactive dendrimers according toclaim 7, wherein Q is O or —NH—.
 15. Photoreactive dendrimers accordingto claim 14, wherein Q is O.
 16. Photoreactive dendrimers according toclaim 7, wherein the groups X and Y represent hydrogen. 17.Photoreactive dendrimers according to claim 7, wherein the photoactivegroups are groups of formula Ia.
 18. Photoreactive dendrimers accordingto claim 7, wherein S₁ is selected from a single covalent bond, —O—,—CO—O—, —O—CO—, —NR¹—, —NR¹—CO—, —CO—NR¹—, —NR¹—CO—O—, —O—CO—NR¹—,—NR¹—C O—NR¹—, —CH═CH—, —C≡C—, —O—CO—O— and a straight-chain or branchedalkylene group, which is optionally substituted by one or more groupsselected from fluorine, chlorine and cyano and in which two or threenon-adjacent alkylene —CH₂— groups are independently optionally replacedby a group D with the proviso that the total number of chain carbonatoms in the alkylene group does not exceed 24, wherein R¹ representshydrogen or lower alkyl.
 19. Photoreactive dendrimers according to claim18, wherein S₁ is selected from a single covalent bond, —CO—O—, —O—CO—,—(CH₂)_(r)—, —(CH₂)_(r)—O—, —(CH₂)_(r)—CO—, —(CH₂)_(r)—CO—O—,—(CH₂)_(r)—O—CO—, —(CH₂)_(r)—CO—NR¹—, —(CH₂)_(r)—NR¹—CO—,—(CH₂)_(r)—NR¹—, —O—(CH₂)_(r)—, —CO—O—(CH₂)_(r)—, —O—CO—(CH₂)_(r)—,—NR¹—CO—(CH₂)_(r)—, —CO—NR¹—(CH₂)_(r)—, —NR¹—(CH₂)_(r)—,—O—(CH₂)_(r)—CO—O—, —O—(CH₂)_(r)—O—CO—, —O—(CH₂)_(r)—CO—NR¹—,—O—(CH₂)_(r)—NR¹—, —O—(CH₂)_(r)—O—, —O—(CH₂)_(r)—NR¹—CO—,—NR¹—(CH₂)_(r)—CO—O—, —NR¹—(CH₂)_(r)—O—, —NR¹—(CH₂)_(r)—NR¹—,—NR¹—(CH₂)_(r)—O—CO—, —CO—NR¹—(CH₂)_(r)—O—, —CO—NR¹—(CH₂)_(r)—NR¹—,—CO—NR¹—(CH₂)_(r)—O—CO—, —O—CO—(CH₂)_(r)—CO—, —O—CO—(CH₂)_(r)—O—,—O—CO—(CH₂)_(r)—NR²—, —O—CO—(CH₂)_(r)—CO—O—, —O—CO—(CH₂)_(r)—CO—NR¹—,—O—CO—(CH₂)_(r)—NR¹—CO—, —(CH₂)_(r)—O—(CH₂)_(s)—,—(CH₂)_(r)—CO—O—(CH₂)_(s)—, —(CH₂)_(r)—O—CO—(CH₂)_(s)—,—(CH₂)_(r)—NR¹—CO—(CH₂)_(s)—, —(CH₂)_(r)—NR¹—CO—O—(CH₂)_(s)—,—(CH₂)_(r)—O—(CH₂)_(s)—O—, —(CH₂)_(r)—CO—O—(CH₂)_(s)—O—,—(CH₂)_(r)—O—CO—(CH₂)_(s)—O—, —(CH₂)_(r)—NR¹—CO—(CH₂)_(s)—O—,—(CH₂)_(r)—NR¹—CO—O—(CH₂)_(s)—O—, —O—(CH₂)_(r)—O—(CH₂)_(s)—,—O—(CH₂)_(r)—CO—O—(CH₂)_(s)—, —O—(CH₂)_(r)—NR¹—CO—(CH₂)_(s)—,—O—(CH₂)_(r)—NR¹—CO—O—(CH₂)_(s)—, —O—(CH₂)_(r)—CO—O—(CH₂)_(s)—O—,—O—(CH₂)_(r)—O—(CH₂)_(s)—O—, —O—(CH₂)_(r)—NR¹—CO—(CH₂)_(s)—O—,—O—(CH₂)_(r)—NR¹—CO—O—(CH₂)_(s)—O—, —CO—O—(CH₂)_(r)—O—(CH₂)_(s)— and—CO—O—(CH₂)_(r)—O—(CH₂)_(s)—O—, wherein R¹ is as defined above, r and seach represent an integer from 1 to 20, preferably from 1 to 12, andr+s≦21, preferably ≦15.
 20. Photoreactive dendrimers according to claim18, wherein S₁ is selected from a single covalent bond, —(CH₂)_(r)—,—(CH₂)_(r)—O—, —(CH₂)_(r)—CO—O—, —(CH₂)_(r)—O—CO—, —(CH₂)_(r)—CO—NH—,—(CH₂)_(r)—NH—CO—, —O—(CH₂)_(r)—, —CO—O—(CH₂)_(r)—, —CO—NH—(CH₂)_(r)—,—O—CO—(CH₂)_(r)—, —O—CO—(CH₂)_(r)—CO—O—, —O—(CH₂)_(r)—O—CO—, —O(CH₂)_(r)CO—NH—, —O—(CH₂)_(r)—NH—CO—, —CO—O—(CH₂)_(r)—O—,|—CO—NH—(CH₂)_(r)—O—,—O—(CH₂)_(r)—O—, —(CH₂)_(r)—NH—CO—(CH₂)_(s)—,—(CH₂)_(r)—NH—CO—O—(CH₂)_(s)—, —(CH₂)_(r)—O—(CH₂)_(s)—O—,—(CH₂)_(r)—NH—CO—(CH₂)_(s)—O—, —(CH₂)_(r)—NH CO—O—(CH₂)_(s)—O—,—O—(CH₂)_(r)—NH—CO—(CH₂)_(s)—, —O—(CH₂)_(r)—O—(CH₂)_(s)—O—,—O—CO—(CH₂)_(r)—O—(CH₂)_(s)—O—, —CO—O—(CH₂)_(r)—O—(CH₂)_(s)—O—,—O—(CH₂)_(r)—NH—CO—(CH₂)_(s)—O— and —O—CO—(CH₂)_(r)—NH—CO—(CH₂)_(s)—O—,wherein r and s each represent an integer from 1 to 12 and r+s≦15. 21.Photoreactive dendrimers according to claim 18, wherein SI includes1,2-ethylene, 1,3-propylene, 1,4-butylene, 1,5-pentylene, 1,6-hexylene,1,7-heptylene, 1,8-octylene, 1,9-nonylene, 1,10-decylene,1,11-undecylene, 1,12-dodecylene, 3-methyl--1,4-butylene,3-propyleneoxy, 3-propyleneoxycarbonyl, 2-ethylenecarbonyloxy,4-butyleneoxy, 4-butyleneoxycarbonyl, 3-propylenecarbonyloxy,5-pentyleneoxy, 5-pentyleneoxycarbonyl, 4-butylenecarbonyloxy,6-hexyleneoxy, 6-hexyleneoxycarbonyl, 5-pentylenecarbonyloxy,7-heptyleneoxy, 7-heptyleneoxycarbonyl, 6-hexylenecarbonyloxy,8-octyleneoxy, 8-octyleneoxycarbonyl, 7-heptylenecarbonyloxy,9-nonyleneoxy, 9-nonyleneoxycarbonyl, 8-octylenecarbonyloxy,10-decyleneoxy, 10-decyleneoxycarbonyl, 9-nonylenecarbonyloxy,11-undecyleneoxy, 11-undecyleneoxycarbonyl, 10-decylenecarbonyloxy,12-dodecyleneoxy, 12-dodecyleneoxycarbonyl, 11-undecylenecarbonyloxy,3-propyleneiminocarbonyl, 4-butyleneiminocarbonyl,5-pentyleneiminocarbonyl, 6-hexyleneiminocarbonyl,7-heptyleneiminocarbonyl, 8-octyleneiminocarbonyl,9-nonyleneiminocarbonyl, 10-decyleneiminocarbonyl,11-undecyleneiminocarbonyl, 12-dodecyleneiminocarbonyl,2-ethylenecarbonylimino, 3-propylenecarbonylimino,4-butylenecarbonylimino, 5-pentylenecarbonylimino,6-hexylenecarbonylimino, 7-heptylenecarbonylimino,8-octylenecarbonylimino, 9-nonylenecarbonylimino,10-decylenecarbonylimino, 11-undecylenecarbonylimino,6-(3-propyleneiminocarbonyloxy)hexylene, 6-(3-propyleneoxy)hexylene,6-(3-propyleneoxy)-hexyloxy, 6-(3-propyleneiminocarbonyloxy)hexyloxy,6-(3-propyleneiminocarbonyl)hexyl, 6-(3-propyleneiminocarbonyl)hexyloxy,1,2-ethylenedioxy, 1,3-propylenedioxy, 1,4-butylenedioxy,1,5-pentylenedioxy, 1,6-hexylenedioxy, 1,7-heptylenedioxy,1,8-octylenedioxy, 1,9-nonylenedioxy, 1,10-decylenedioxy,1,11-undecylenedioxy, 1,12-dodecylenedioxy and the like. 22.Photoreactive dendrimers according to claim 7, wherein S₂ is selectedfrom a single covalent bond, a straight-chain or branched alkylenegroup, which is optionally substituted by one or more groups selectedfrom fluorine, chlorine and cyano and in which two or three non-adjacentalkylene —CH₂— groups are independently optionally replaced by a group Dwith the proviso that the total number of chain carbon atoms in thealkylene group does not exceed 24, wherein R¹ represents hydrogen orlower alkyl.
 23. Photoreactive dendrimers according to claim 22, whereinS₂ is selected from a single covalent bond, —(CH₂)_(r)—, —(CH₂)_(r)—O—,—(CH₂)_(r)—CO—, —(CH₂)_(r)—CO—O—, —(CH₂)_(r)—O—CO—, —(CH₂)_(r)—CO—NR¹—,—(CH₂)_(r)—NR¹—CO—, —(CH₂)_(r)—NR¹—, —(CH₂)_(r)—O—(CH₂)_(s)—,—(CH₂)_(r)—CO—O—(CH₂)_(s)—, —(CH₂)_(r)—O—CO—(CH₂)_(s)—,—(CH₂)_(r)—NR¹—CO—(CH₂)_(s)—, —(CH₂)_(r)—NR¹—CO—O—(CH₂)_(s)—,—(CH₂)_(r)—O—(CH₂)_(s)—O—, —(CH₂)_(r)—CO—O—(CH₂)_(s)—O—,—(CH₂)_(r)—O—CO—(CH₂)_(s)—O—, —(CH₂)_(r)—NR¹—CO—(CH₂)_(s)—O—,—(CH₂)_(r)—NR¹—CO—O—(CH₂)_(s)—O—, —(CH₂)_(r)—O—(CH₂)_(s)—CO—O— and—(CH₂)_(r)—O—(CH₂)_(s)—O—CO—, wherein R¹ is as defined herein above; rand s each represent an integer from 1 to 20; and r+s≦21. It is morepreferred that r and s each represent an integer from 1 to
 12. It isespecially preferred that r+s≦15.
 24. Photoreactive dendrimers accordingto claim 22, wherein S₂ includes 1,2-ethylene, 1,3-propylene,1,4-butylene, 1,5-pentylene, 1,6-hexylene, 1,7-heptylene, 1,8-octylene,1,9-nonylene, 1,10-decylene, 1,11-undecylene, 1,12-dodecylene,3-methyl-1,4-butylene, 3-propyleneoxy, 3-propyleneoxycarbonyl,2-ethylenecarbonyloxy, 4-butyleneoxy, 4-butyleneoxycarbonyl,3-propylenecarbonyloxy, 5-pentyleneoxy, 5-pentyleneoxycarbonyl,4-butylenecarbonyloxy, 6-hexyleneoxy, 6-hexyleneoxycarbonyl,5-pentylenecarbonyloxy, 7-heptyleneoxy, 7-heptyleneoxycarbonyl,6-hexylenecarbonyloxy, 8-octyleneoxy, 8-octyleneoxycarbonyl,7-heptylenecarbonyloxy, 9-nonyleneoxy, 9-nonyleneoxycarbonyl,8-octylenecarbonyloxy, 10-decyleneoxy, 10-decyleneoxycarbonyl,9-nonylenecarbonyloxy, 11-undecyleneoxy, 11-undecyleneoxycarbonyl,10-decylenecarbonyloxy, 12-dodecylencoxy, 12-dodecyleneoxycarbonyl,11-undecylenecarbonyloxy, 3-propyleneiminocarbonyl,4-butyleneiminocarbonyl, 5-pentyleneiminocarbonyl,6-hexyleneiminocarbonyl, 7-heptyleneiminocarbonyl,8-octyleneiminocarbonyl, 9-nonyleneiminocarbonyl,10-decyleneiminocarbonyl, 11-undecyleneiminocarbonyl,12-dodecyleneiminocarbonyl, 2-ethylenecarbonylimino,3-propylenecarbonylimino, 4-butylenecarbonylimino,5-pentylenecarbonylimino, 6-hexylene-carbonylimino,7-heptylenecarbonylimino, 8-octylenecarbonylimino,9-nonylenecarbonylimino, 10-decylenecarbonylimino,11-undecylenecarbonylimino, 6-(3-propyleneiminocarbonyloxy)-hexylene,6-(3-propyleneoxy)hexylene, 6-(3-propyleneoxy)hexyloxy,6-(3-propyleneiminocarbonyloxy)hexyloxy,6-(3-propyleneiminocarbonyl)hexylene,6-(3-propyleneiminocarbonyl)-hexyloxy and the like.
 25. Photoreactivedendrimers according to claim 1, wherein the terminal moieties can alsobe hydrogen; or a group like group B which is able to react or interactwith a second material like polymers, oligomers, monomers, photoactivepolymers, photoactive oligomers and/or photoactive monomers or surfaces;or an unit such as a straight-chain or branched alkyl group which isunsubstituted, mono or poly-substituted by fluorine, chlorine, cyano,having 1 to 24 carbon atoms, wherein one or more —CH₂— groups mayindependently be replaced by a group D, with the proviso that oxygenatoms are not directly attached to each other.
 26. Photoreactivedendrimers according to claim 1, wherein at least four terminal moietiesare photoactive groups.
 27. Photoreactive dendrimers according to claim1, wherein the number of branching units per dendrimer is at least 3.28. Photoreactive dendrimers according to claim 1, wherein the branchingunits are represented by dendritic blocks of the general formulae IIa,IIb or a combination of them, for example formula IIc:

wherein the broken line indicates the point of linkage to the coreportion or to the Z units of the previous generation of branching units;and the full line indicates the point of linkage to the E residue of thenext generation of branching units or the point of linkage to theterminal groups; and wherein E represents an organic residue; Zrepresents a single bond or a spacer unit such as a straight-chain orbranched alkylene group which is unsubstituted, mono or poly-substitutedby fluorine, chlorine, having 1 to 24 carbon atoms, wherein one or more—CH₂— groups may independently be replaced by a group D, with theproviso that oxygen atoms are not directly attached to each other, or Zmay also represent a photoreactive group like groups represented bygeneral formula Ia and Ib wherein B in this case indicates the point oflinkage to E and wherein A, S₁, S₂, Q, X and Y are as defined above. 29.Photoreactive dendrimers according to claim 28, wherein the branchingunits are groups of formula Ia and groups of formula IIc, while groupsof formula IIb, if present, are favorably located in the outermostgeneration.
 30. Photoreactive dendrimers according to claim 29, whereinthe dendritic blocks are groups of formulae Ia.
 31. Photoreactivedendrimers according to claim 28, wherein the groups E are aromatic,alicyclic or CR¹— units wherein R¹ has the meaning defined above. 32.Photoreactive dendrimers according to claim 31, wherein the groups E areselected form 1,2,3-benzenetriyl, 1,3,4-benzenetriyl, 1,3,5-benzenetriylor a group CR¹—.
 33. Photoreactive dendrimers according to claim 28,wherein Z is selected form from a single covalent bond, —O—, —CO—O—,NR¹—, —NR¹—CO—, —CO—NR¹—, —NR¹—CO—O—, —O—CO—NR¹—, —NR¹—C O—NR¹—,—CH═CH—, —C≡C—, —O—CO—O— and a straight-chain or branched alkylenegroup, which is optionally substituted by one or more groups selectedfrom fluorine, chlorine and cyano and in which one up to fournon-adjacent alkylene —CH₂— groups are independently optionally replacedby a group D with the proviso that the total number of chain carbonatoms in the alkylene group does not exceed 30 and wherein R¹ representshydrogen or lower alkyl.
 34. Photoreactive dendrimers according to claim33, wherein Z represents photoreactive groups like groups represented bygeneral formula Ia and Ib wherein B in this case indicates the point oflinkage to E and wherein A, S₁, S₂, Q, X and Y are as defined above. 35.Photoreactive dendrimers according to claim 33, wherein Z includes1,2-ethylene, 1,3-propylene, 1,4-butylene, 1,5-pentylene, 1,6-hexylene,1,7-heptylene, 1,8-octylene, 1,9-nonylene, 1,10-decylene,1,11-undecylene, 1,12-dodecylene, 3-methyl--1,4-butylene,3-propyleneoxy, 3-propyleneoxycarbonyl, 2-ethylenecarbonyloxy,4-butyleneoxy, 4-butyleneoxycarbonyl, 3-propylenecarbonyloxy,5-pentyleneoxy, 5-pentyleneoxycarbonyl, 4-butylenecarbonyloxy,6-hexyleneoxy, 6-hexyleneoxycarbonyl, 5-pentylenecarbonyloxy,7-heptyleneoxy, 7-heptyleneoxycarbonyl, 6-hexylenecarbonyloxy,8-octyleneoxy, 8-octyleneoxycarbonyl, 7-heptylenecarbonyloxy,9-nonyleneoxy, 9-nonyleneoxycarbonyl, 8-octylenecarbonyloxy,10-decyleneoxy, 10-decyleneoxycarbonyl, 9-nonylenecarbonyloxy,11-undecyleneoxy, 11-undecyleneoxycarbonyl, 10-decylenecarbonyloxy,12-dodecyleneoxy, 12-dodecyleneoxycarbonyl, 11-undecylenecarbonyloxy,3-propyleneiminocarbonyl, 4-butyleneiminocarbonyl,5-pentyleneiminocarbonyl, 6-hexyleneiminocarbonyl,7-heptyleneiminocarbonyl, 8-octyleneiminocarbonyl,9-nonyleneiminocarbonyl, 10-decyleneiminocarbonyl,11-undecyleneiminocarbonyl, 12-dodecyleneiminocarbonyl,2-ethylenecarbonylimino, 3-propylenecarbonylimino,4-butylenecarbonylimino, 5-pentylenecarbonylimino,6-hexylenecarbonylimino, 7-heptylenecarbonylimino,8-octylenecarbonylimino, 9-nonylenecarbonylimino,10-decylenecarbonylimino, 11-undecylenecarbonylimino,6-(3-propyleneiminocarbonyloxy)hexylene, 6-(3-propyleneoxy)hexylene,6-(3-propyleneoxy)-hexyloxy, 6-(3-propyleneiminocarbonyloxy)hexyloxy,6-(3-propyleneiminocarbonyl)hexyl, 6-(3-propyleneiminocarbonyl)hexyloxy,1,2-ethylenedioxy, 1,3-propylenedioxy, 1,4-butylenedioxy,1,5-pentylenedioxy, 1,6-hexylenedioxy, 1,7-heptylenedioxy,1,8-octylenedioxy, 1,9-nonylenedioxy, 1,10-decylenedioxy,1,11-undecylenedioxy, 1,12-dodecylenedioxy,2-{4-[4-(2-oxyethyl)cyclohexyl]phenyl}ethoxy,2-[4′-(4-oxybutyl)-1,1′biphenyl-4-yl]ethoxy,2-{4-[4-(2-oxy-ethyl)phenyl}ethoxy,2-{4-[4-(2-carbonyloxyethyl)-cyclohexyl]phenyl}ethoxy,2-[4′-(4-carbonyloxybutyl)-1,1′biphenylene-4-yl]ethoxy,6-{4-[4-(2-carbonyloxyethyl)phenyl}hexyloxy,5-{[4′-(4-oxybutoxy)-1,1′-biphenyl-4-yl]oxy}pentylcarbonyloxy,2-oxyethylene, 3-oxypropylene, 4-oxybutylene, 5-oxypentylene,6-oxyhexylene, 7-oxyheptylene, 8-oxyoctylene, 9-oxynonylene,10-oxydecylene, 11-oxyundecylene, 12-oxydodecylene,2-(oxycarbonyl)ethylene, 3-(oxycarbonyl)propylene,4-(oxycarbonyl)butylene, 5-(oxycarbonyl)pentylene,6-(oxycarbonyl)hexylene, 7-(oxycarbonyl)heptylene,8-(oxycarbonyl)octylene, 9-(oxycarbonyl)-nonylene,10-(oxycarbonyl)decylene, 11-(oxycarbonyl)undecylene,12-(oxycarbonyl)-dodecylene, 2-(carbonyloxy)ethylene,3-(carbonyloxy)propylene, 4-(carbonyloxy)butylene,5-(carbonyloxy)pentylene, 6-(carbonyloxy)hexylene,7-(carbonyloxy)heptylene, 8-(carbonyloxy)octylene,9-(carbonyloxy)nonylene, 10-(carbonyloxy)decylene,11-(carbonyloxy)undecylene, 12-(carbonyloxy)dodecylene,2-(carbonylimino)ethylene, 3-(carbonylimino)propylene,4-(carbonylimino)butylene, 5-(carbonylimino)pentylene,6-(carbonylimino)hexylene, 7-(carbonylimino)heptylene,8-(carbonylimino)octylene, 9-(carbonylimino)nonylene,10-(carbonylimino)decylene, 11-(carbonylimino)undecylene,12-(carbonylimino)dodecylene, 2-iminoethylene, 3-iminopropylene,4-iminobutylene, 5-iminopentylene, 6-iminohexylene, 7-iminoheptylene,8-iminooctylene, 9-iminononylene, 10-iminodecylene, 11-iminoundecylene,12-iminododecylene, 2-iminocarbonylethylene, 3-iminocarbonylpropylene,4-iminocarbonylbutylene, 5-iminocarbonylpentylene,6-iminocarbonylhexylene, 7-iminocarbonylheptylene,8-iminocarbonyloctylene, 9-iminocarbonylnonylene,10-iminocarbonyldecylene, 11-iminocarbonylundecylene,12-iminocarbonyldodecylene, 2-(2-ethyleneoxy)ethylene,2-(3-propyleneoxy)ethylene, 6-(4-butyleneoxy)hexylene,2-(2-ethyleneiminocarbonyl)ethylene,2-(3-propyleneiminocarbonyl)ethylene,6-(4-butyleneiminocarbonyl)hexylene,6-(3-propyleneiminocarbonyloxy)hexylene,6-(3-propyleneiminocarbonyl)hexylene,6-oxyhexyl(2E)-3-[4-(4-oxybutoxy)-3-methoxyphenyl]-2-propenoate,8-oxyoctyl(2E)-3-[4-(5-oxypentoxy)phenyl]-2-propenoate,6-oxyhexyl(2E)-3-[4-(4-(carbonyloxy)butoxy)-3-methoxyphenyl]-2-propenoate,8-(oxycarbonyl)octyl(2E)-3-[4-(5-oxypentoxy)phenyl]-2-propenoate and thelike.
 36. Photoreactive dendrimers according to any preceding claim 1,wherein the core portion is covalently bonded to one, two, three or fourdendritic blocks and are represented by formulae IIIa, IIIb, IIIc, IIIdand IIIe:

wherein the broken line indicates the point of linkage with a branchingunit and wherein F represents a single bond or a unit such as astraight-chain or branched alkylene group which is unsubstituted, monoor poly-substituted by fluorine, chlorine, having 1 to 40 carbon atoms,wherein one or more —CH₂— groups may independently be replaced by agroup D, with the proviso that oxygen atoms are not directly attached toeach other, or F represents a photoreactive group like groupsrepresented by general formula Ia and Ib wherein B in this caseindicates the point of linkage to the first generation of the dendrimer;G represents hydrogen; a group which is able to react or interact with asecond material like polymers, oligomers, monomers, photoactivepolymers, photoactive oligomers and/or photoactive monomers or surfaces;or a monomer repeating unit in a homo or copolymer from a radical orcationic polymerisation; K represents a nitrogen atom, a carbon atom, agroup CR¹— or an aromatic or alicyclic group, which is optionallysubstituted by a group selected from fluorine, chlorine, cyano and aC₁-18 cyclic, straight-chain or branched alkyl group, which isoptionally substituted by a single cyano group or by one or more halogenatoms and in which one or more non-adjacent alkyl —CH₂— groups areoptionally replaced by a group selected from —O—, —CO—, —CO—O—, —O—CO—,—Si(CH₃)₂—O—Si(CH₃)₂—, —NR¹—, —NR¹—CO—, —CO—NR¹—, —NR¹—CO—O—,—O—CO—NR¹—, —NR¹—CO—NR¹—, —CH═CH—, —C≡C— and —O—CO—O—, wherein R¹represents hydrogen or lower alkyl; and J represents a carbon atom or anaromatic or alicyclic group, which is optionally substituted by a groupselected from fluorine, chlorine, cyano and a C₁₋₁₈ cyclic,straight-chain or branched alkyl group, which is optionally substitutedby a single cyano group or by one or more halogen atoms and in which oneor more non-adjacent alkyl —CH₂— groups are optionally replaced by agroup selected from —O—, —CO—, —CO—O—, —O—CO—, —Si(CH₃)₂—O—Si(CH₃)₂—,—NR¹—, —NR¹—CO—, —CO—NR¹—, —NR¹—CO—O—, —O—CO—NR¹—, —NR¹—CO—NR¹—,—CH═CH—, —C≡C— and —O—CO—O—, wherein R¹ represents hydrogen or loweralkyl.
 37. Photoreactive dendrimers according to claim 36, wherein F isselected from a single covalent bond, —O—, —CO—O—, —O—CO—, —NR¹—,—NR¹—CO—, —CO—NR¹—, —NR¹—CO—O—, —O—CO—NR¹—, —NR¹—CO—NR¹—, —CH═CH—,—C≡C—, —O—CO—O— and a straight-chain or branched alkylene group, whichis optionally substituted by one or more groups selected from fluorine,chlorine and cyano and in which up to four non-adjacent alkylene —CH₂—groups are independently optionally replaced by a group D with theproviso that the total number of chain carbon atoms in the alkylenegroup does not exceed 30, wherein R¹ represents hydrogen or lower alkyl.38. Photoreactive dendrimers according to claim 37, wherein F representsphotoreactive groups like a group represented by general formula Ia orIb, wherein B in this case indicates the point of linkage to the firstgeneration of the dendrimer and wherein A, S₁, S₂, Q, X and Y are asdefined above.
 39. Photoreactive dendrimers according to claim 37,wherein F includes 1,2-ethylene, 1,3-propylene, 1,4-butylene,1,5-pentylene, 1,6-hexylene, 1,7-heptylene, 1,8-octylene, 1,9-nonylene,1,10-decylene, 1,11-undecylene, 1,12-dodecylene, 3-methyl--1,4-butylene,3-propyleneoxy, 3-propyleneoxycarbonyl, 2-ethylenecarbonyloxy,4-butyleneoxy, 4-butyleneoxycarbonyl, 3-propylenecarbonyloxy,5-pentyleneoxy, 5-pentyleneoxycarbonyl, 4-butylenecarbonyloxy,6-hexyleneoxy, 6-hexyleneoxycarbonyl, 5-pentylenecarbonyloxy,7-heptyleneoxy, 7-heptyleneoxycarbonyl, 6-hexylenecarbonyloxy,8-octyleneoxy, 8-octyleneoxycarbonyl, 7-heptylenecarbonyloxy,9-nonyleneoxy, 9-nonyleneoxycarbonyl, 8-octylenecarbonyloxy,10-decyleneoxy, 10-decyleneoxycarbonyl, 9-nonylenecarbonyloxy,11-undecyleneoxy, 11-undecyleneoxycarbonyl, 10-decylenecarbonyloxy,12-dodecyleneoxy, 12-dodecyleneoxycarbonyl, 11-undecylenecarbonyloxy,3-propyleneiminocarbonyl, 4-butyleneiminocarbonyl,5-pentyleneiminocarbonyl, 6-hexyleneiminocarbonyl,7-heptyleneiminocarbonyl, 8-octyleneiminocarbonyl,9-nonyleneiminocarbonyl, 10-decyleneiminocarbonyl,11-undecyleneiminocarbonyl, 12-dodecyleneiminocarbonyl,2-ethylenecarbonylimino, 3-propylenecarbonylimino,4-butylenecarbonylimino, 5-pentylenecarbonylimino,6-hexylenecarbonylimino, 7-heptylenecarbonylimino,8-octylenecarbonylimino, 9-nonylenecarbonylimino,10-decylenecarbonylimino, 11-undecylenecarbonylimino,6-(3-propyleneiminocarbonyloxy)hexylene, 6-(3-propyleneoxy)hexylene,6-(3-propyleneoxy)-hexyloxy, 6-(3-propyleneiminocarbonyloxy)hexyloxy,6-(3-propyleneiminocarbonyl)hexyl, 6-(3-propyleneiminocarbonyl)hexyloxy,1,2-ethylenedioxy, 1,3-propylenedioxy, 1,4-butylenedioxy,1,5-pentylenedioxy, 1,6-hexylenedioxy, 1,7-heptylenedioxy,1,8-octylenedioxy, 1,9-nonylenedioxy, 1,10-decylenedioxy,1,11-undecylenedioxy, 1,12-dodecylenedioxy,2-{4-[4-(2-oxyethyl)cyclohexyl]phenyl}ethoxy,2-[4′-(4-oxybutyl)-1,1′biphenyl-4-yl]ethoxy,2-{4-[4-(2-oxy-ethyl)phenyl}ethoxy,2-{4-[4-(2-carbonyloxyethyl)-cyclohexyl]phenyl}ethoxy,2-[4′-(2-carbonyloxybutyl)-1,1′biphenylene-4-yl]ethoxy,6-{4-[4-(2-carbonyloxyethyl)phenyl}hexyloxy,5-{[4′-(4-oxybutoxy)-1,1′-biphenyl-4-yl]oxy}pentylcarbonyloxy,2-oxyethylene, 3-oxypropylene, 4-oxybutylene, 5-oxypentylene,6-oxyhexylene, 7-oxyheptylene, 8-oxyoctylene, 9-oxynonylene,10-oxydecylene, 11-oxyundecylene, 12-oxydodecylene,2-(oxycarbonyl)ethylene, 3-(oxycarbonyl)propylene,4-(oxycarbonyl)butylene, 5-(oxycarbonyl)pentylene,6-(oxycarbonyl)hexylene, 7-(oxycarbonyl)heptylene,8-(oxycarbonyl)octylene, 9-(oxycarbonyl)-nonylene,110-(oxycarbonyl)decylene, 11-(oxycarbonyl)undecylene,12-(oxycarbonyl)-dodecylene, 2-(carbonyloxy)ethylene,3-(carbonyloxy)propylene, 4-(carbonyloxy)butylene,5-(carbonyloxy)pentylene, 6-(carbonyloxy)hexylene,7-(carbonyloxy)heptylene, 8-(carbonyloxy)octylene,9-(carbonyloxy)nonylene, 110-(carbonyloxy)decylene,11-(carbonyloxy)undecylene, 12-(carbonyloxy)dodecylene,2-(carbonylimino)ethylene, 3-(carbonylimino)propylene,4-(carbonylimino)butylene, 5-(carbonylimino)pentylene,6-(carbonylimino)hexylene, 7-(carbonylimino)heptylene,8-(carbonylimino)octylene, 9-(carbonylimino)nonylene,110-(carbonylimino)decylene, 11-(carbonylimino)undecylene,12-(carbonylimino)dodecylene, 2-iminoethylene, 3-iminopropylene,4-iminobutylene, 5-iminopentylene, 6-iminohexylene, 7-iminoheptylene,8-iminooctylene, 9-iminononylene, 10-iminodecylene, 11-iminoundecylene,12-iminododecylene, 2-iminocarbonylethylene, 3-iminocarbonylpropylene,4-iminocarbonylbutylene, 5-iminocarbonylpentylene,6-iminocarbonylhexylene, 7-iminocarbonylheptylene,8-iminocarbonyloctylene, 9-iminocarbonylnonylene,10-iminocarbonyldecylene, 11-iminocarbonylundecylene,12-iminocarbonyldodecylene, 2-(2-ethyleneoxy)ethylene,2-(3-propyleneoxy)ethylene, 6-(4-butyleneoxy)hexylene,2-(2-ethyleneiminocarbonyl)ethylene,2-(3-propyleneiminocarbonyl)ethylene,6-(4-butyleneiminocarbonyl)hexylene,6-(3-propyleneiminocarbonyloxy)hexylene,6-(3-propyleneiminocarbonyl)hexylene,6-oxyhexyl(2E)-3-[4-(4-oxybutoxy)-3-methoxyphenyl]-2-propenoate,8-oxyoctyl(2E)-3-[4-(5-oxypentoxy)phenyl]-2-propenoate,1,11-bis-[(2E)-3-(4-oxyphenyl)-2-propenoate]undecylene and the like 40.Photoreactive dendrimers according to anyone of claims 36 to 39, whereinG is selected from hydrogen; a radically or cationically polymerizablegroup, or also from mono-, di- or tri-alkoxy or halogeno silanes. 41.Photoreactive dendrimers according to claim 40, wherein G is selectedfrom hydrogen, a radically or cationically polymerizable group or amonomer unit in a homo or copolymer from a radical or cationicpolymerisation.
 42. Photoreactive dendrimers according to claim 40,wherein G is a radically or cationically polymerizable group. 43.Photoreactive dendrimers according to claim 36, wherein K is a nitrogenatom, a carbon atom, an aromatic, an alicyclic or a CR¹— unit wherein R¹is as defined above.
 44. Photoreactive dendrimers according to claim 43,wherein K is selected form 1,2,3-benzenetriyl, 1,3,4-benzenetriyl,1,3,5-benzenetriyl or a group CR¹—.
 45. Photoreactive dendrimersaccording to claim 36, wherein J is a carbon atom, an aromatic or analicyclic unit.
 46. Photoreactive dendrimers according to claim 45,wherein J is a carbon atom.
 47. Photoreactive dendrimers according toclaim 36, wherein the core portions are groups of formulae IIIa, IIIb,IIIc, IIId.
 48. Photoreactive dendrimers according to claim 47, whereinthe core portions are groups of formulae IIIa and IIIb. 49.Photoreactive dendrimers according to claim 1 further comprisingadditives such as silane-containing compounds and epoxy-containingcross-linking agents,
 50. Photoreactive dendrimers according to claim49, wherein the epoxy-containing crosslinking agents include4,4′-methylenebis(N,N-diglycidylaniline), trimethylolpropane triglycidylether, benzene-1,2,4,5-tetracarboxylic acid1,2:4,5-N,N′-diglycidyldiimide, polyethylene glycol diglycidyl ether,and N,N-diglycidyl-cyclohexylamine.
 51. Photoreactive dendrimersaccording to claim 1 further comprising additives such as aphotosensitiser, a photoradical generator and/or a cationicphotoinitiator.
 52. Photoreactive dendrimers according to claim 51,wherein the photoactive additives include 2,2-dimethoxyphenylethanone, amixture of diphenylmethanone and N,N-dimethylbenzenamine or ethyl4-(dimethylamino)benzoate, xanthone, thioxanthone, IRGACURE™ 184, 369,500, 651 and 907, Michler's ketone and triaryl sulfonium salts. 53.Photoreactive dendrimers according to claim 1 which, when irradiatedover a relatively short time with polarized light, result in stable,high-resolution patternable orientation layers.
 54. Orientation layersfor liquid crystals and in the construction of unstructured andstructured optical elements and multi-layer systems made by using one ormore photoreactive dendrimers.
 55. Orientation layers for liquidcrystals and in the construction of unstructured and structured opticalelements and multi-layer systems comprising one or more photoreactivedendrimers in at least partially crosslinked form.
 56. Orientationlayers according to claim 54, wherein the photoreactive dendrimers areas defined according to claim
 1. 57. Orientation layers according toclaim 54, further comprising polymers, oligomers, monomers, photoactivepolymers, photoactive oligomers and/or photoactive monomers.
 58. Opticalelement comprising one or more photoactive dendrimers in at leastpartially crosslinked form.
 59. Optical element according to claim 57,wherein the photoreactive dendrimers are as defined according toclaim
 1. 60. Electrooptical components comprising one or moreorientation layer according to claim
 54. 61. Use of photoreactivedendrimers alone or in combination with polymers, oligomers, monomers,photoactive polymers, photoactive oligomers and/or photoactive monomersin the production of orientation layers for liquid crystals.
 62. Use ofphotoreactive dendrimers alone or in combination with polymers,oligomers, monomers, photoactive polymers, photoactive oligomers and/orphotoactive monomers in the construction of unstructured and structuredoptical elements and multi-layer systems.
 63. Use according to claim 61,wherein the photoreactive dendrimers are as defined according to claim1.